Plan clock
- Status
- Approved, expires 2028-02-22
- Plan
- PDC 08 Northern Virginia Hazard Mitigation Plan (FEMA plan 108862)
- Approved
- 2023-02-23
- Expires
- 2028-02-22
- As of
- 2026-09-28
- Days
- 512 days to expiry
- Update underway
- FEMA tracker shows a plan in progress
What changed since your last plan (approved 2023-02-23)
- New federal declarations
- EM-3631-VA (1 declaration row; 1 counted incident)
- Storm Events records since approval
- 177 (data through 2026-06-30)
- Repetitive loss now
- FMA RL 3, SRL 7 (44 CFR 77.2); any definition: 103
- Repeat-flood change
- First release: no prior release to compare.
Sources
FEMA, OpenFEMA HazardMitigationPlanStatuses v1, version 2026-09-26T121003Z, pulled 2026-09-28, https://www.fema.gov/api/open/v1/HazardMitigationPlanStatuses (API)
FEMA, OpenFEMA DisasterDeclarationsSummaries v2, version 2026-09-27T010817Z, pulled 2026-09-28, https://www.fema.gov/api/open/v2/DisasterDeclarationsSummaries (API)
NOAA NCEI, NOAA NCEI Storm Events Database, details files (csvfiles v1.0), version c20260918, pulled 2026-09-28, https://www.ncei.noaa.gov/pub/data/swdi/stormevents/csvfiles/
FEMA, OpenFEMA NfipMultipleLossProperties v1, version 2026-08-04T164045Z, pulled 2026-09-28, https://www.fema.gov/api/open/v1/NfipMultipleLossProperties (API)
Plan status for every jurisdiction listed in this county
| Jurisdiction | Type | Status | Plan | Approved | Expires | Days to expirynegative = days since expiry | Update underway | Notes |
|---|---|---|---|---|---|---|---|---|
| Fairfax County | County | Approved, expires 2028-02-22 | PDC 08 Northern Virginia Hazard Mitigation Plan (FEMA plan 108862) | 2023-02-23 | 2028-02-22 | 512 | FEMA tracker shows a plan in progress | member approved 2023-06-27 |
| Clifton town | Town | Approved, expires 2028-02-22 | PDC 08 Northern Virginia Hazard Mitigation Plan (FEMA plan 108862) | 2023-02-23 | 2028-02-22 | 512 | FEMA tracker shows a plan in progress | member approved 2023-05-02 |
| Herndon town | Town | Approved, expires 2028-02-22 | PDC 08 Northern Virginia Hazard Mitigation Plan (FEMA plan 108862) | 2023-02-23 | 2028-02-22 | 512 | FEMA tracker shows a plan in progress | member approved 2023-09-12 |
| Vienna town | Town | Approved, expires 2028-02-22 | PDC 08 Northern Virginia Hazard Mitigation Plan (FEMA plan 108862) | 2023-02-23 | 2028-02-22 | 512 | FEMA tracker shows a plan in progress | member approved 2023-04-10 |
Plan 108862 also covers 16 other participants not listed on this page (named in the XLSX file).
Source
FEMA, OpenFEMA HazardMitigationPlanStatuses v1, version 2026-09-26T121003Z, pulled 2026-09-28, https://www.fema.gov/api/open/v1/HazardMitigationPlanStatuses (API)
State plan status and tribal plans in this state: see the state page.
Supports B1-a: hazards
Hazards NRI does not cover: check locally
- dam failure (incl. upstream dams)
- levee failure
- flash flood as its own subtype
- ice jams
- debris flows
- erosion (riverine and coastal)
- land subsidence and sinkholes
- expansive soils
The 18 National Risk Index hazards, ranked by expected annual loss (EAL)
| Rank by EAL | Hazard | NRI risk rating | EAL rating | EAL buildingsmodeled dollars per year | EAL agriculturemodeled dollars per year | EAL population equivalencestatistical value of life and injury, $13.7M per life, not property damage | EAL total (see note)modeled dollars per year | Storm Events records since 1996count | Evidence for an omissionNRI Not Applicable, no declaration and no Storm Events record since 1996 | Storm Events coverage note |
|---|---|---|---|---|---|---|---|---|---|---|
| 1 | Inland Flooding | Relatively High | Relatively High | $152,745,731 | $14,141 | $1,960,504 | $154,720,376 | 529 | ||
| 2 | Hurricane | Relatively Moderate | Relatively High | $17,478,888 | $5,009 | $519,842 | $18,003,739 | 5 | ||
| 3 | Heat Wave | Relatively High | Relatively High | $952 | $11 | $12,528,360 | $12,529,322 | 62 | ||
| 4 | Earthquake | Relatively Moderate | Relatively Moderate | $7,784,347 | $3,286,138 | $11,070,485 | Not in Storm Events. Storm Events coverage of this hazard is limited; absence is not evidence of low risk. | |||
| 5 | Cold Wave | Relatively Moderate | Relatively High | $245,840 | $574 | $5,651,965 | $5,898,380 | 49 | Includes 32 Frost/Freeze records, event types the NRI definition of this hazard leaves out. | |
| 6 | Strong Wind | Relatively High | Relatively High | $1,281,537 | $12,237 | $3,014,462 | $4,308,237 | 708 | Includes 16 High Wind records and 24 Strong Wind records, event types the NRI definition of this hazard leaves out. | |
| 7 | Hail | Relatively High | Relatively High | $4,017,135 | $168 | $7,700 | $4,025,003 | 145 | ||
| 8 | Lightning | Very High | Very High | $219,259 | $3,673,265 | $3,892,524 | 15 | |||
| 9 | Tornado | Relatively Low | Relatively Low | $954,406 | $37 | $968,938 | $1,923,380 | 12 | ||
| 10 | Winter Weather | Very High | Very High | $224,918 | under $1 | $1,594,150 | $1,819,068 | 169 | ||
| 11 | Ice Storm | Relatively Moderate | Relatively High | $571,426 | $45,935 | $617,361 | 5 | |||
| 12 | Coastal Flooding | Relatively Low | Relatively Low | $228,044 | $2,017 | $230,060 | 3 | |||
| 13 | Drought | Relatively Low | Relatively Low | $46,917 | $46,917 | 10 | ||||
| 14 | Wildfire | Very Low | Very Low | $21,583 | under $1 | $2,783 | $24,366 | 0 | No recorded events in Storm Events since 1996 (data through 2026-06-30). Storm Events coverage of this hazard is limited; absence is not evidence of low risk. | |
| 15 | Landslide | Relatively Low | Relatively Low | $10,107 | $265 | $10,371 | 0 | Declared 1 time; no Storm Events record of this type. Storm Events coverage of this hazard is limited; absence is not evidence of low risk. | ||
| Avalanche | Not Applicable | Not Applicable | 0 | NRI rates avalanche Not Applicable for this county, and no federal declaration for this county names it. | No recorded events in Storm Events since 1996 (data through 2026-06-30). | |||||
| Tsunami | Insufficient Data | Insufficient Data | 0 | No recorded events in Storm Events since 1996 (data through 2026-06-30). Storm Events coverage of this hazard is limited; absence is not evidence of low risk. | ||||||
| Volcanic Activity | Not Applicable | Not Applicable | 0 | NRI rates volcanic activity Not Applicable for this county, and no federal declaration for this county names it. | No recorded events in Storm Events since 1996 (data through 2026-06-30). Storm Events coverage of this hazard is limited; absence is not evidence of low risk. |
Total = buildings + agriculture + population equivalence; FEMA values each expected death (or 10 injuries) at $13.7 million (2024 dollars).
Sources
FEMA, FEMA National Risk Index 1.20.0 (December 2025), county and census tract tables, version 1.20.0, pulled 2026-09-28, https://www.fema.gov/about/reports-and-data/openfema/nri/v120/NRI_Table_Counties.zip (download, 25 MB), https://www.fema.gov/about/reports-and-data/openfema/nri/v120/NRI_Table_CensusTracts.zip (download, 635 MB)
NOAA NCEI, NOAA NCEI Storm Events Database, details files (csvfiles v1.0), version c20260918, pulled 2026-09-28, https://www.ncei.noaa.gov/pub/data/swdi/stormevents/csvfiles/
Check your state hazard mitigation plan's hazard list for this county; explain any hazard you drop.
Supports B1-b: location
Where each hazard occurs
| Hazard | Location | Census tracts ratedrated of all tracts |
|---|---|---|
| Avalanche | Census tract rating counts from the National Risk Index tract table (see B1-f). Tract maps and place names are not in this packet. | 0 of 274 |
| Coastal Flooding | The FEMA Flood Insurance Rate Map (FIRM) is the required location source for flooding. See the FEMA Flood Map Service Center (https://msc.fema.gov) for this county. | 21 of 274 |
| Cold Wave | Affects the whole planning area; national data do not distinguish locations within the county. Confirm locally. | 274 of 274 |
| Drought | Affects the whole planning area; national data do not distinguish locations within the county. Confirm locally. | 11 of 274 |
| Earthquake | Census tract rating counts from the National Risk Index tract table (see B1-f). Tract maps and place names are not in this packet. | 274 of 274 |
| Hail | Affects the whole planning area; national data do not distinguish locations within the county. Confirm locally. | 274 of 274 |
| Heat Wave | Affects the whole planning area; national data do not distinguish locations within the county. Confirm locally. | 274 of 274 |
| Hurricane | Census tract rating counts from the National Risk Index tract table (see B1-f). Tract maps and place names are not in this packet. | 274 of 274 |
| Ice Storm | Affects the whole planning area; national data do not distinguish locations within the county. Confirm locally. | 274 of 274 |
| Inland Flooding | The FEMA Flood Insurance Rate Map (FIRM) is the required location source for flooding. See the FEMA Flood Map Service Center (https://msc.fema.gov) for this county. | 274 of 274 |
| Landslide | Census tract rating counts from the National Risk Index tract table (see B1-f). Tract maps and place names are not in this packet. | 274 of 274 |
| Lightning | Affects the whole planning area; national data do not distinguish locations within the county. Confirm locally. | 274 of 274 |
| Strong Wind | Affects the whole planning area; national data do not distinguish locations within the county. Confirm locally. | 274 of 274 |
| Tornado | Census tract rating counts from the National Risk Index tract table (see B1-f). Tract maps and place names are not in this packet. | 274 of 274 |
| Tsunami | Census tract rating counts from the National Risk Index tract table (see B1-f). Tract maps and place names are not in this packet. | 0 of 274 |
| Volcanic Activity | Census tract rating counts from the National Risk Index tract table (see B1-f). Tract maps and place names are not in this packet. | 0 of 274 |
| Wildfire | Census tract rating counts from the National Risk Index tract table (see B1-f). Tract maps and place names are not in this packet. | 249 of 274 |
| Winter Weather | Affects the whole planning area; national data do not distinguish locations within the county. Confirm locally. | 274 of 274 |
Source
FEMA, FEMA National Risk Index 1.20.0 (December 2025), county and census tract tables, version 1.20.0, pulled 2026-09-28, https://www.fema.gov/about/reports-and-data/openfema/nri/v120/NRI_Table_Counties.zip (download, 25 MB), https://www.fema.gov/about/reports-and-data/openfema/nri/v120/NRI_Table_CensusTracts.zip (download, 635 MB)
Supports B1-c: extent
Extent: scale, observed range and worst recorded event per hazard
| Hazard | Scale | Recordscount, years | Observed range | Worst recorded event | Most damaging (when different) | How it applies to members | Note |
|---|---|---|---|---|---|---|---|
| Avalanche | none (count and damage) | 0 | Physical measure: in event narratives only; local data required. | ||||
| Coastal Flood, Storm Surge/Tide | none in data (FIRM for depth) | 3, 1996 to 2011 (2 zone-level) | Storm Surge/Tide, 1996-09-06, $250,000 property; crops not reported (1996 dollars) | No event record names a member place. Zone-level records (2) apply countywide. | Flood depth: see the FEMA Flood Insurance Rate Map. | ||
| Cold/Wind Chill, Extreme Cold/Wind Chill | wind chill | 17, 1998 to 2026 (17 zone-level) | 1 day to 11 days (median 2 days); 15 with a recorded value | 11 consecutive days, 2026-01-23 to 2026-02-02, zone-level | Zone-level records: applies countywide; national data do not locate these events within the county. | Wind chill: in event narratives only; local data required. | |
| Frost/Freeze (outside NRI Cold Wave definition) | crop damage | 32, 2005 to 2021 (32 zone-level) | No crop damage reported in 32 records. | Zone-level records: applies countywide; national data do not locate these events within the county. | Temperature: in event narratives only; local data required. | ||
| Drought | US Drought Monitor D-scale | 10, 1998 to 2007 (10 zone-level) | 29 days to 140 days (median 45.5 days); 4 with a recorded value | 140 days (about 4.6 months), 1999-05-01 to 1999-09-17, a run of 5 consecutive Storm Events drought records, zone-level | Zone-level records: applies countywide; national data do not locate these events within the county. | Storm Events enters a drought at D2 or worse east of the Rockies and D3 or worse from the Rockies west (NWS Instruction 10-1605); NRI drought counts D3 and D4 only. | |
| Earthquake | Modified Mercalli (local data) | 0 | No Storm Events record; local data required (e.g., USGS). | ||||
| Hail | hail size (inches) | 182, 1961 to 2026 | 0.5 in to 3 in (median 1 in); 182 with a recorded value | 3 in hail, 2004-08-11; same size also recorded on 1980-04-09 | Hail, 1999-04-23, $3,000,000 property; crops not reported (1999 dollars) | Event records naming member places: Herndon town (13 records), Vienna town (7 records), Clifton town (5 records). | |
| Excessive Heat, Heat | heat index (narratives) | 62, 1996 to 2024 (62 zone-level) | 1 day to 8 days (median 2 days); 45 with a recorded value | 8 consecutive days, 2002-08-12 to 2002-08-19, zone-level | Zone-level records: applies countywide; national data do not locate these events within the county. | Heat index: in event narratives only; local data required. Heat records from November to March (unseasonable warmth, not a heat wave) are counted but not used for the longest run. | |
| Hurricane, Tropical Storm, Tropical Depression | Saffir-Simpson | 5, 1999 to 2020 (5 zone-level) | Strongest recorded (records with damage, a wind speed or direct casualties first, then storm type, category and wind): Tropical Storm record, 2003-09-18 to 2003-09-19, $18,000,000 property; $10,000 crops, reported for the zone (2003 dollars); NWS zone VAZ053 (FAIRFAX), zone-level: may include parts of neighboring counties | Zone-level records: applies countywide; national data do not locate these events within the county. | Storm Events files every zone of a storm's episode under the storm's event type and category, so a Hurricane (Typhoon) record, especially an inland or remnant one, does not by itself mean hurricane-force winds here; read the damage and wind columns. | ||
| Ice Storm | Sperry-Piltz (local data) | 5, 1999 to 2021 (5 zone-level) | Ice Storm, 1999-01-14, $20,000 property; crops not reported, reported for the zone (1999 dollars); NWS zone VAZ053 (FAIRFAX), zone-level: may include parts of neighboring counties | Zone-level records: applies countywide; national data do not locate these events within the county. | Ice thickness: in event narratives only; local data required. | ||
| Flash Flood, Flood, Lakeshore Flood | damage and flood days (FIRM for depth) | 529, 1996 to 2026 (12 zone-level) | Flash Flood, 2006-06-25, $11,000,000 property; crops not reported (2006 dollars) | Event records naming member places: Vienna town (14 records), Herndon town (10 records), Clifton town (6 records). Zone-level records (12) apply countywide. | Flood depth: see the FEMA Flood Insurance Rate Map. Storm Events damage can be $0 or blank even for a major flood, so the worst record here may not be the worst flood; compare FEMA Public Assistance by declaration in B1-d. | ||
| Debris Flow | none (count and damage) | 0 | Physical measure: in event narratives only; local data required. | ||||
| Lightning | annualized frequency (the measure FEMA's Local Mitigation Planning Handbook names) | 15, 1997 to 2008 | Lightning, 2002-04-28, $1,200,000 property; crops not reported (2002 dollars) | Event records naming member places: Herndon town (1 record). | Storm Events lists lightning with damage or casualties; physical measure in event narratives only; local data required. | ||
| High Wind and Strong Wind (outside NRI Strong Wind definition) | wind speed (kt and mph) | 40, 1996 to 2025 (39 zone-level) | 30 kt (35 mph) to 59 kt (68 mph) (median 50 kt (58 mph)); 23 with a recorded value | 59 kt (68 mph) measured gust, High Wind, 2023-04-01; NWS zone VAZ053 (FAIRFAX), zone-level: may include parts of neighboring counties | Strong Wind, 2003-11-13, $1,000,000 property; crops not reported, reported for the zone (2003 dollars) | No event record names a member place. Zone-level records (39) apply countywide. | |
| Thunderstorm Wind | wind speed (kt and mph) | 735, 1956 to 2026 | 35 kt (40 mph) to 78 kt (90 mph) (median 50 kt (58 mph)); 651 with a recorded value | 78 kt (90 mph) measured, Thunderstorm Wind, 2000-05-13 | Thunderstorm Wind, 2006-07-02, $5,000,000 property; crops not reported (2006 dollars) | Event records naming member places: Clifton town (19 records), Vienna town (17 records), Herndon town (15 records). | |
| Tornado | Enhanced Fujita (F before Feb 2007) | 22, 1952 to 2022 | F/EF0 to F/EF3 (median F/EF0); 22 with a recorded value | F3 tornado, 1973-04-01, 7.1 mi path length (records before 1996 may include the whole path; rating and listing come from the county where the tornado began), 100 yd wide, $25,000,000 property; crops not recorded (1973 dollars), 37 direct injuries | Event records naming member places: Clifton town (1 record), Herndon town (1 record). | From 1996 on, tornado records are per-county segments and length is the path length within this county (NWS Instruction 10-1605); records before 1996 may give the whole path length, including the path outside this county, and before 1996 a tornado is listed once, under the county where it began, with the whole path's rating; counties farther along the path may not list it. Length is not used to rank tornadoes. | |
| Tsunami | none (count and damage) | 0 | Physical measure: in event narratives only; local data required. | ||||
| Volcanic Ash, Volcanic Ashfall | Volcanic Explosivity Index (local data) | 0 | Physical measure: in event narratives only; local data required. | ||||
| Wildfire | acres burned (local data) | 0 | Acres burned: in event narratives only; local data required. | ||||
| Winter Storm, Heavy Snow, Blizzard, Lake-Effect Snow, Winter Weather, Sleet | none in data (snowfall local) | 169, 1996 to 2026 (169 zone-level) | Heavy Snow, 2006-02-12, $200,000 property; crops not reported, reported for the zone (2006 dollars); NWS zone VAZ053 (FAIRFAX), zone-level: may include parts of neighboring counties | Zone-level records: applies countywide; national data do not locate these events within the county. | Snow depth: in event narratives only; local data required. |
Storm Events records are more complete after 1996; before 1996 only Tornado (from 1950), Hail and Thunderstorm Wind (from 1955) exist. Zone-level records are placed with NWS zone-county files, which exist from 2020 on; an earlier record is placed by its zone number in the nearest later file only when its zone name matches that file, records from zones NWS renumbered are placed by name or left out, and a record whose zone is in no known file is left out of every count, so counts before 2020 can be low. Some current zones are also missing from the NWS files, so recent counts can be low too.
Dollars are nominal (as reported), labeled with the year; not adjusted for inflation.
Sources
NOAA NCEI, NOAA NCEI Storm Events Database, details files (csvfiles v1.0), version c20260918, pulled 2026-09-28, https://www.ncei.noaa.gov/pub/data/swdi/stormevents/csvfiles/
NOAA National Weather Service, NWS county-public forecast zones correlation file, version bp03mr20 to bp16ap26 (11 files; newest bp16ap26), pulled 2026-09-28, https://www.weather.gov/gis/ZoneCounty
Supports B1-d: previous occurrences
- Declaration rows
- 19
- Counted incidents
- 16
Federal disaster declarations for this county
| Declared | Incident began | FEMA number | Type | Title | Mapped hazard | County Public Assistancefederal share obligated, nominal dollars | Flags | Notes |
|---|---|---|---|---|---|---|---|---|
| 2026-01-23 | 2026-01-22 | EM-3631-VA | Emergency | SEVERE WINTER STORM | Winter Weather | none found | new since last plan; within last 5 years | |
| 2020-04-02 | 2020-01-20 | DR-4512-VA | Major disaster | COVID-19 PANDEMIC | Non-natural, not counted | $200,306,101.65 | ||
| 2020-03-13 | 2020-01-20 | EM-3448-VA | Emergency | COVID-19 | Non-natural, not counted | none found | same incident as DR-4512 | |
| 2018-09-11 | 2018-09-13 | EM-3403-VA | Emergency | HURRICANE FLORENCE | Hurricane | none found | ||
| 2016-03-07 | 2016-01-22 | DR-4262-VA | Major disaster | SEVERE WINTER STORM AND SNOWSTORM | Winter Weather | $3,568,301.97 | ||
| 2012-10-29 | 2012-10-26 | EM-3359-VA | Emergency | HURRICANE SANDY | Hurricane | none found | ||
| 2011-11-17 | 2011-09-08 | DR-4045-VA | Major disaster | THE REMNANTS OF TROPICAL STORM LEE | Hurricane | $1,043,677.11 | ||
| 2010-04-27 | 2010-02-05 | DR-1905-VA | Major disaster | SEVERE WINTER STORMS AND SNOWSTORMS | Winter Weather | $3,259,635.36 | ||
| 2010-02-16 | 2009-12-18 | DR-1874-VA | Major disaster | SEVERE WINTER STORM AND SNOWSTORM | Winter Weather | $1,391,090.82 | ||
| 2006-07-13 | 2006-06-23 | DR-1655-VA | Major disaster | SEVERE STORMS, TORNADOES, AND FLOODING | Inland Flooding; Tornado | $1,521,172.99 | ||
| 2005-09-12 | 2005-08-29 | EM-3240-VA | Emergency | HURRICANE KATRINA EVACUATION | Hurricane: evacuation support, not a local hazard event; not counted | none found | ||
| 2003-09-18 | 2003-09-18 | DR-1491-VA | Major disaster | HURRICANE ISABEL | Hurricane | $2,170,861.87 | ||
| 2003-03-27 | 2003-02-15 | DR-1458-VA | Major disaster | SEVERE WINTER STORM, RECORD/NEAR RECORD SNOWFALL, HEAVY RAIN,FLOODIND, AND MUDSLIDE | Inland Flooding; Landslide; Winter Weather | $496,618.78 | ||
| 2000-02-28 | 2000-01-25 | DR-1318-VA | Major disaster | SEVERE WINTER STORMS | Winter Weather | $226,890.70 | ||
| 1999-09-18 | 1999-09-13 | DR-1293-VA | Major disaster | HURRICANE FLOYD MAJOR DISASTER DECLARATIONS | Hurricane | PA not declared for this county | ||
| 1996-01-13 | 1996-01-06 | DR-1086-VA | Major disaster | BLIZZARD OF 96 (SEVERE SNOW STORM) | Winter Weather | none found | ||
| 1993-03-25 | 1993-03-13 | EM-3112-VA | Emergency | SEVERE WINTER STORM | Winter Weather | none found | ||
| 1977-01-26 | 1977-01-26 | DR-525-VA | Major disaster | ICE CONDITIONS | Cold Wave | PA not declared for this county | ||
| 1972-06-23 | 1972-06-23 | DR-339-VA | Major disaster | TROPICAL STORM AGNES | Inland Flooding (primary); also designated: Hurricane | none found |
County Public Assistance: applicants the FEMA record places in this county, including any state agencies FEMA files there; statewide rows are listed on the state page; federal share obligated, nominal dollars.
Dollars are nominal (as reported), labeled with the year; not adjusted for inflation.
Sources
FEMA, OpenFEMA DisasterDeclarationsSummaries v2, version 2026-09-27T010817Z, pulled 2026-09-28, https://www.fema.gov/api/open/v2/DisasterDeclarationsSummaries (API)
FEMA, OpenFEMA PublicAssistanceFundedProjectsSummaries v1, version 2026-09-26T151157Z, pulled 2026-09-28, https://www.fema.gov/api/open/v1/PublicAssistanceFundedProjectsSummaries (API)
FEMA, OpenFEMA HazardMitigationPlanStatuses v1, version 2026-09-26T121003Z, pulled 2026-09-28, https://www.fema.gov/api/open/v1/HazardMitigationPlanStatuses (API)
Statewide declarations
| Declared | Incident began | FEMA number | Type | Title | Mapped hazard | Flags | Notes |
|---|---|---|---|---|---|---|---|
| 1963-03-21 | 1963-03-21 | DR-149-VA | Major disaster | FLOODS | Inland Flooding | ||
| 1962-03-09 | 1962-03-09 | DR-123-VA | Major disaster | SEVERE STORMS, HIGH TIDES & FLOODING | Inland Flooding (primary); also designated: Coastal Flooding | ||
| 1957-02-01 | 1957-02-01 | DR-68-VA | Major disaster | FLOODS | Inland Flooding |
FEMA recorded these with designated area Statewide and no county. Listed on every county page in the state; not counted with county rows.
Source
FEMA, OpenFEMA DisasterDeclarationsSummaries v2, version 2026-09-27T010817Z, pulled 2026-09-28, https://www.fema.gov/api/open/v2/DisasterDeclarationsSummaries (API)
Public Assistance filed under this county for declarations that do not list it: 2 rows, $295,804.59
| FEMA number | Declared | Title | Applicant | PA obligatedfederal share obligated, nominal dollars |
|---|---|---|---|---|
| DR-4092-VA | 2012-11-26 | HURRICANE SANDY | Fairfax, City of | $127,206.37 |
| DR-4072-VA | 2012-07-27 | SEVERE STORMS AND STRAIGHT-LINE WINDS | Fairfax, City of | $168,598.22 |
FEMA's Public Assistance summaries file these applicants under this county, but FEMA's declaration rows for these disasters do not designate it (an electric cooperative or district serving several counties, for example). Not in any declaration row above and not counted.
Sources
FEMA, OpenFEMA PublicAssistanceFundedProjectsSummaries v1, version 2026-09-26T151157Z, pulled 2026-09-28, https://www.fema.gov/api/open/v1/PublicAssistanceFundedProjectsSummaries (API)
FEMA, OpenFEMA DisasterDeclarationsSummaries v2, version 2026-09-27T010817Z, pulled 2026-09-28, https://www.fema.gov/api/open/v2/DisasterDeclarationsSummaries (API)
Previous occurrences by hazard, with explicit no-event rows
| Hazard | Storm Events recordsfull period | Since plan approvalrecords | During plan reviewrecords | Last 5 yearsrecords | Declared incidentsdistinct incidents | Declared since approvaldistinct incidents | Period | Statement |
|---|---|---|---|---|---|---|---|---|
| Avalanche | 0 | 0 | 0 | 0 | 0 | 0 | 1996 to 2026-06-30 | No recorded events, 1996 to 2026-06-30, NOAA NCEI Storm Events |
| Coastal Flooding | 3 | 0 | 0 | 0 | 0 | 0 | 1996 to 2026-06-30 | |
| Cold Wave | 49 | 4 | 1 | 5 | 1 | 0 | 1996 to 2026-06-30 | Includes 32 Frost/Freeze records, event types the NRI definition of this hazard leaves out. |
| Drought | 10 | 0 | 0 | 0 | 0 | 0 | 1996 to 2026-06-30 | |
| Earthquake | 0 | 0 | 0 | 0 | 0 | 0 | No Storm Events record; local data required (e.g., USGS). | |
| Hail | 182 | 8 | 2 | 10 | 0 | 0 | 1955 to 2026-06-30 | |
| Heat Wave | 62 | 3 | 0 | 3 | 0 | 0 | 1996 to 2026-06-30 | |
| Hurricane | 5 | 0 | 0 | 0 | 6 | 0 | 1996 to 2026-06-30 | |
| Ice Storm | 5 | 0 | 0 | 0 | 0 | 0 | 1996 to 2026-06-30 | |
| Inland Flooding | 529 | 51 | 22 | 86 | 3 | 0 | 1996 to 2026-06-30 | |
| Landslide | 0 | 0 | 0 | 0 | 1 | 0 | 1996 to 2026-06-30 | No Storm Events records of this type; 1 federal declared incident (see declarations table) |
| Lightning | 15 | 0 | 0 | 0 | 0 | 0 | 1996 to 2026-06-30 | |
| Strong Wind | 775 | 97 | 36 | 137 | 0 | 0 | 1955 to 2026-06-30 | Includes 16 High Wind records and 24 Strong Wind records, event types the NRI definition of this hazard leaves out. |
| Tornado | 22 | 0 | 2 | 2 | 1 | 0 | 1950 to 2026-06-30 | |
| Tsunami | 0 | 0 | 0 | 0 | 0 | 0 | 1996 to 2026-06-30 | No recorded events, 1996 to 2026-06-30, NOAA NCEI Storm Events |
| Volcanic Activity | 0 | 0 | 0 | 0 | 0 | 0 | 1996 to 2026-06-30 | No recorded events, 1996 to 2026-06-30, NOAA NCEI Storm Events |
| Wildfire | 0 | 0 | 0 | 0 | 0 | 0 | 1996 to 2026-06-30 | No recorded events, 1996 to 2026-06-30, NOAA NCEI Storm Events |
| Winter Weather | 169 | 14 | 2 | 21 | 8 | 1 | 1996 to 2026-06-30 |
Sources
NOAA NCEI, NOAA NCEI Storm Events Database, details files (csvfiles v1.0), version c20260918, pulled 2026-09-28, https://www.ncei.noaa.gov/pub/data/swdi/stormevents/csvfiles/
FEMA, OpenFEMA DisasterDeclarationsSummaries v2, version 2026-09-27T010817Z, pulled 2026-09-28, https://www.fema.gov/api/open/v2/DisasterDeclarationsSummaries (API)
NOAA National Weather Service, NWS county-public forecast zones correlation file, version bp03mr20 to bp16ap26 (11 files; newest bp16ap26), pulled 2026-09-28, https://www.weather.gov/gis/ZoneCounty
Notable Storm Events records
| Date | Event type | Magnitude or extent | Damagenominal dollars | Direct deaths, injuriesindirect not counted | Location | Flags | Why listed |
|---|---|---|---|---|---|---|---|
| 2026-01-23 | Extreme Cold/Wind Chill | damage not reported | 0, 0 | NWS zone VAZ053 (FAIRFAX), zone-level: may include parts of neighboring counties | new since last plan; within last 5 years | B1-c worst recorded: Cold/Wind Chill, Extreme Cold/Wind Chill | |
| 2025-05-16 | Thunderstorm Wind | 56 kt (64 mph) estimated gust | $25,000 property; crops not reported (2025 dollars) | 1, 0 | GUM SPGS | new since last plan; within last 5 years | deaths or injuries recorded |
| 2023-04-01 | High Wind | 59 kt (68 mph) measured gust | $0 property; $0 crops, reported for the zone (2023 dollars) | 0, 0 | NWS zone VAZ053 (FAIRFAX), zone-level: may include parts of neighboring counties | new since last plan; within last 5 years | B1-c worst recorded: High Wind and Strong Wind (outside NRI Strong Wind definition) |
| 2016-12-17 | Winter Weather | damage not reported | 1, 4 | NWS zone VAZ053 (FAIRFAX), zone-level: may include parts of neighboring counties | deaths or injuries recorded | ||
| 2006-06-25 | Flash Flood | $11,000,000 property; crops not reported (2006 dollars) | 0, 0 | HUNTINGTON | B1-c worst recorded: Flash Flood, Flood, Lakeshore Flood | ||
| 2004-08-11 | Hail | 3 in | damage not reported | 0, 0 | ANNANDALE | B1-c worst recorded: Hail | |
| 2003-09-18 | Tropical Storm | $18,000,000 property; $10,000 crops, reported for the zone (2003 dollars) | 0, 0 | NWS zone VAZ053 (FAIRFAX), zone-level: may include parts of neighboring counties | B1-c worst recorded: Hurricane, Tropical Storm, Tropical Depression | ||
| 2002-08-12 | Heat | damage not reported | 0, 0 | NWS zone VAZ053 (FAIRFAX), zone-level: may include parts of neighboring counties | B1-c worst recorded: Excessive Heat, Heat | ||
| 2002-04-28 | Lightning | $1,200,000 property; crops not reported (2002 dollars) | 0, 0 | OAKTON | B1-c worst recorded: Lightning | ||
| 2000-05-13 | Thunderstorm Wind | 78 kt (90 mph) measured | damage not reported | 0, 0 | FT BELVOIR | B1-c worst recorded: Thunderstorm Wind | |
| 1979-09-05 | Tornado | F3, 17.9 mi path length (records before 1996 may include the whole path; rating and listing come from the county where the tornado began), 300 yd wide | $2,500,000 property; crops not recorded (1979 dollars) | 1, 6 | location not recorded | deaths or injuries recorded | |
| 1973-04-01 | Tornado | F3, 7.1 mi path length (records before 1996 may include the whole path; rating and listing come from the county where the tornado began), 100 yd wide | $25,000,000 property; crops not recorded (1973 dollars) | 0, 37 | location not recorded | B1-c worst recorded: Tornado |
The full list is in the XLSX file, sheet "B1-d Storm Events history" (1,826 rows).
Storm Events records are more complete after 1996; before 1996 only Tornado (from 1950), Hail and Thunderstorm Wind (from 1955) exist. Zone-level records are placed with NWS zone-county files, which exist from 2020 on; an earlier record is placed by its zone number in the nearest later file only when its zone name matches that file, records from zones NWS renumbered are placed by name or left out, and a record whose zone is in no known file is left out of every count, so counts before 2020 can be low. Some current zones are also missing from the NWS files, so recent counts can be low too.
Sources
NOAA NCEI, NOAA NCEI Storm Events Database, details files (csvfiles v1.0), version c20260918, pulled 2026-09-28, https://www.ncei.noaa.gov/pub/data/swdi/stormevents/csvfiles/
NOAA National Weather Service, NWS county-public forecast zones correlation file, version bp03mr20 to bp16ap26 (11 files; newest bp16ap26), pulled 2026-09-28, https://www.weather.gov/gis/ZoneCounty
FEMA, OpenFEMA HazardMitigationPlanStatuses v1, version 2026-09-26T121003Z, pulled 2026-09-28, https://www.fema.gov/api/open/v1/HazardMitigationPlanStatuses (API)
State-declared emergencies are not in federal data. Add them from your state emergency management agency.
Tribal and special-area declarations in this state are listed on the state page.
Supports B1-e: probability
Probability: FEMA annualized frequency and descriptor per hazard
| Hazard | FEMA annualized frequency (modeled)unit per row | Unit | In plain terms | Descriptor | Descriptor basis | NRI events or days in its record period (hail, wind and tornado are area-weighted, so can be fractional) | NRI period | Location | Note |
|---|---|---|---|---|---|---|---|---|---|
| Avalanche | events per year | 1994 to 2023 (30 years) | see B1-f | Not Applicable in NRI for this county; no descriptor. | |||||
| Coastal Flooding | 3.76 | events per year at a location (modeled) | about 3.8 per year at a given location in the county | Highly likely | FEMA annualized frequency (modeled) | not shown | modeled | see B1-f | Descriptor from NRI: the rate at a location is 1 or more a year, so the county rate is at least that. |
| Cold Wave | 1.36 | event-days per year | about 1.36 days per year | Likely | event-days in 9 of 30 years, 1996 to 2025 (30%) | 25.4 | 2005-11-12 to 2024-11-12 (19 years) | countywide | NRI gives about 1.36 cold wave event-days a year here (its annualized frequency over 19 years; not its event count divided by the years), but Storm Events has a record in only 9 of 30 years. NRI counts from a different source that records far more events than Storm Events, so this descriptor reads much lower than NRI's frequency; read the two together. Frost/Freeze records are not counted in this descriptor: they record crop freezes, not cold waves. |
| Drought | 2.17 | event-days per year | about 2.17 days per year | Likely | event-days in 3 of 30 years, 1996 to 2025 (10%) | 133 | 2000 to 2025 (25.25 years; D3 and D4 only) | countywide | NRI gives about 2.17 drought event-days a year here (its annualized frequency over 25.25 years; not its event count divided by the years), but Storm Events has a record in only 3 of 30 years. NRI counts from a different source that records far more events than Storm Events, so this descriptor reads much lower than NRI's frequency; read the two together. |
| Earthquake | 0.00124 | annual probability at a location | chance a given location in the county has at least minor-damage shaking in a year: 0.124% | not shown | modeled | see B1-f | Descriptor not assigned: the NRI value is the chance at a location in the county, not how often the hazard affects the county, and Storm Events does not record earthquakes. | ||
| Hail | 3.91 | events per year | about 3.91 per year | Highly likely | FEMA annualized frequency (modeled) | 151.7 (modeled) | 1986 to 2023 (38 years) | countywide | |
| Heat Wave | 5.88 | event-days per year | about 5.88 days per year | Likely | event-days in 20 of 30 years, 1996 to 2025 (66.7%) | 97.7 | 2005-11-12 to 2024-11-12 (19 years) | countywide | |
| Hurricane | 0.0914 | events per year | about 1 in 11 years | Possible | FEMA annualized frequency (modeled) | 22 | 1851 to 2024 (Atlantic) | see B1-f | NRI counts hurricane and tropical storm tracks passing within storm-force wind range; federal declarations are counted separately in B1-d and need not match. |
| Ice Storm | 0.556 | event-days per year | about 0.556 days per year | Likely | event-days in 5 of 30 years, 1996 to 2025 (16.7%) | 38 | 1946-12-31 to 2014-02-12 (67 years) | countywide | |
| Inland Flooding | 5.82 | event-days per year | about 5.82 days per year | Highly likely | event-days in 29 of 30 years, 1996 to 2025 (96.7%) | 163 | 1996 to 2023 (28 years) | see B1-f | |
| Landslide | 0.335 | events per year (modeled) | about 1 in 3 years | Likely | FEMA annualized frequency (modeled) | not shown | modeled | see B1-f | |
| Lightning | 40.9 | days per year with a strike | about 40.9 days per year | Highly likely | FEMA annualized frequency (modeled) | not shown | 1995 to 2023 (29 years; CONUS) | countywide | |
| Strong Wind | 7.78 | events per year | about 7.78 per year | Highly likely | FEMA annualized frequency (modeled) | 295 | 1986 to 2023 (38 years) | countywide | |
| Tornado | 0.298 | events per year | about 1 in 3 years | Likely | FEMA annualized frequency (modeled) | not shown | 1950 to 2023 (EF2+); 1986 to 2023 (EF0-1) | see B1-f | |
| Tsunami | annual probability at the most exposed location (used in place of a county value) | Storm Events records in 0 of 30 years, 1996 to 2025 (0%) | not shown | modeled | see B1-f | No Storm Events record of this hazard, 1996 to 2025; descriptor not assigned (the NRI value is the chance at a location in the county, not how often the hazard affects the county) | |||
| Volcanic Activity | annual probability | not shown | modeled | see B1-f | Not Applicable in NRI for this county; no descriptor. | ||||
| Wildfire | 0.0000212 | annual probability at a location | chance a given location in the county burns in a year: 0.00212% | Storm Events records in 0 of 30 years, 1996 to 2025 (0%) | not shown | modeled | see B1-f | No Storm Events record of this hazard, 1996 to 2025; descriptor not assigned (the NRI value is the chance at a location in the county, not how often the hazard affects the county) | |
| Winter Weather | 9.74 | event-days per year | about 9.74 days per year | Highly likely | event-days in 29 of 30 years, 1996 to 2025 (96.7%) | 182 | 2005-11-12 to 2024-11-12 (19 years) | countywide |
FEMA annualized frequency (modeled) comes from the National Risk Index v1.20 (December 2025). It is not recorded events divided by years, and what it measures depends on the hazard. For most hazards it estimates how often the hazard affects this county each year: it counts events or event-days (drought, heat wave, cold wave, winter weather, ice storm and inland flooding are in days per year; lightning is the number of days per year with a recorded cloud-to-ground strike, from the NOAA Storm Prediction Center daily lightning climatology); it may count events in the surrounding area (hail, strong wind, tornado, hurricane and ice storm use a 49 km grid and buffers) and is averaged over the county's area; and some hazards use a minimum value for places with no recorded event. Earthquake, wildfire and coastal flooding are different: FEMA computes them for each census block and averages them over the county, so the value is the chance (for coastal flooding, the modeled number of floods per year) at a location in the county, which is lower than the chance that the hazard strikes somewhere in the county. Earthquake is the chance of at least minor-damage shaking (U.S. Geological Survey model); wildfire is the chance that a location burns in a large fire (U.S. Forest Service burn probability); coastal flooding comes from FEMA flood zones and NOAA high-tide flooding, so it can be above 1 where high-tide flooding is frequent. Tsunami is the value at the county's most exposed location, from recorded events and modeled return periods. For these four hazards the packet gives no "1 in N years" and takes the descriptor from Storm Events (none for earthquake) unless the value is 1 or more a year. Landslide is a U.S. Geological Survey modeled county rate spread by slope susceptibility. Volcanic activity is the chance that a volcano affecting the county erupts in a year. Drought counts only extreme and exceptional drought (D3 and D4). Source: FEMA, National Risk Index Technical Documentation v1.20, sections 5.2.2 (Table 5), 5.2.3, 7.4, 10.4, 16.5, 17.1, 17.3.1, 17.5, 20.3.1, 21.4, 22.4 and 6 to 23.
Sources
FEMA, FEMA National Risk Index 1.20.0 (December 2025), county and census tract tables, version 1.20.0, pulled 2026-09-28, https://www.fema.gov/about/reports-and-data/openfema/nri/v120/NRI_Table_Counties.zip (download, 25 MB), https://www.fema.gov/about/reports-and-data/openfema/nri/v120/NRI_Table_CensusTracts.zip (download, 635 MB)
NOAA NCEI, NOAA NCEI Storm Events Database, details files (csvfiles v1.0), version c20260918, pulled 2026-09-28, https://www.ncei.noaa.gov/pub/data/swdi/stormevents/csvfiles/
Descriptor scale used in this packet (defined per unit)
| Unit | Descriptor | Definition |
|---|---|---|
| events per year | Highly likely | 1 or more per year |
| events per year | Likely | about once in 1 to 10 years |
| events per year | Possible | about once in 10 to 100 years |
| events per year | Unlikely | less than once in 100 years |
| annual probability | Likely | 10% to under 100% chance in a given year |
| annual probability | Possible | 1% to under 10% chance in a given year |
| annual probability | Unlikely | under 1% chance in a given year |
| event-days (share of years) | Highly likely | event-days recorded in 90% or more of years |
| event-days (share of years) | Likely | event-days recorded in 10% to under 90% of years |
| event-days (share of years) | Possible | event-days recorded in some years but under 10% of years |
| lightning strike-days | Highly likely | cloud-to-ground strikes on 1 or more days per year |
Sources
FEMA, FEMA National Risk Index 1.20.0 (December 2025), county and census tract tables, version 1.20.0, pulled 2026-09-28, https://www.fema.gov/about/reports-and-data/openfema/nri/v120/NRI_Table_Counties.zip (download, 25 MB), https://www.fema.gov/about/reports-and-data/openfema/nri/v120/NRI_Table_CensusTracts.zip (download, 635 MB)
NOAA NCEI, NOAA NCEI Storm Events Database, details files (csvfiles v1.0), version c20260918, pulled 2026-09-28, https://www.ncei.noaa.gov/pub/data/swdi/stormevents/csvfiles/
Intensity bands: historical frequency (Storm Events)
| Hazard | Band | Years | Eventscounty-coded records | Years in period | Events per yearevents / years |
|---|---|---|---|---|---|
| Hail | 1.00-1.99 in | 1996 to 2025 | 92 | 30 | 3.07 |
| Hail | 2.00 in+ | 1996 to 2025 | 7 | 30 | 0.233 |
| Strong Wind (Thunderstorm Wind records) | 50-64 kt | 1996 to 2025 | 589 | 30 | 19.6 |
| Strong Wind (Thunderstorm Wind records) | 65 kt+ | 1996 to 2025 | 15 | 30 | 0.5 |
| Strong Wind (Thunderstorm Wind records) | unmeasured or below 50 kt | 1996 to 2025 | 54 | 30 | 1.8 |
| Tornado | EF0-1 | 1996 to 2025 | 10 | 30 | 0.333 |
| Tornado | EF2-3 | 1996 to 2025 | 2 | 30 | 0.0667 |
| Tornado | EF4-5 | 1996 to 2025 | 0 | 30 | 0 |
| Tornado | unrated (EFU) | 1996 to 2025 | 0 | 30 | 0 |
Hail smaller than 1 inch is not counted: on 2010-01-05 the National Weather Service raised its severe-hail threshold from 3/4 inch to 1 inch, so smaller reports became less common after 2009 (NWS Service Change Notice 09-52). NRI hail frequency uses a 0.75 inch threshold.
Source
NOAA NCEI, NOAA NCEI Storm Events Database, details files (csvfiles v1.0), version c20260918, pulled 2026-09-28, https://www.ncei.noaa.gov/pub/data/swdi/stormevents/csvfiles/
Optional: future conditions. Not a required item in the 2025 FEMA Local Mitigation Planning Policy Guide; some states ask for it. The federal Climate Mapping for Resilience and Adaptation (CMRA) site gives county exposure to future climate conditions.
Supports B1-f: variation across the planning area
Range of census tract risk within the county
| Hazard | Tractsrated of all | Risk score minNRI score, 0 to 100 | Median | Max | Tracts by rating | Note |
|---|---|---|---|---|---|---|
| Avalanche | 0 of 274 | Not Applicable 274 | ||||
| Coastal Flooding | 21 of 274 | 70.0 | 78.3 | 92.5 | Relatively Moderate 3, Relatively Low 10, Very Low 8, No Rating 253 | |
| Cold Wave | 274 of 274 | 15.9 | 29.1 | 49.2 | Relatively Moderate 5, Relatively Low 265, Very Low 4 | National data give a county-wide or coarse (49 km grid or NWS zone) frequency for this hazard, so they cannot show members' hazard differing. The tract range above mostly reflects where buildings and people are. Confirm locally. |
| Drought | 11 of 274 | 78.4 | 82.2 | 87.1 | Relatively Low 9, Very Low 2, No Rating 263 | National data give a county-wide or coarse (49 km grid or NWS zone) frequency for this hazard, so they cannot show members' hazard differing. Agriculture is all of NRI's expected annual loss for this hazard in the county, so the tract range above mostly reflects where crop and livestock value is, not where buildings and people are. Confirm locally. |
| Earthquake | 274 of 274 | 7.3 | 47.6 | 80.1 | Relatively Moderate 2, Relatively Low 172, Very Low 100 | |
| Hail | 274 of 274 | 22.6 | 57.4 | 86.6 | Relatively Moderate 32, Relatively Low 229, Very Low 13 | National data give a county-wide or coarse (49 km grid or NWS zone) frequency for this hazard, so they cannot show members' hazard differing. The tract range above mostly reflects where buildings and people are. Confirm locally. |
| Heat Wave | 274 of 274 | 1.5 | 47.6 | 80.5 | Relatively Moderate 82, Relatively Low 183, Very Low 9 | National data give a county-wide or coarse (49 km grid or NWS zone) frequency for this hazard, so they cannot show members' hazard differing. The tract range above mostly reflects where buildings and people are. Confirm locally. |
| Hurricane | 274 of 274 | 48.1 | 67.5 | 86.4 | Relatively Moderate 19, Relatively Low 252, Very Low 3 | |
| Ice Storm | 274 of 274 | 2.5 | 22.5 | 69.5 | Relatively Moderate 1, Relatively Low 53, Very Low 220 | National data give a county-wide or coarse (49 km grid or NWS zone) frequency for this hazard, so they cannot show members' hazard differing. The tract range above mostly reflects where buildings and people are. Confirm locally. |
| Inland Flooding | 274 of 274 | 0.5 | 29.0 | 92.2 | Relatively High 11, Relatively Moderate 73, Relatively Low 117, Very Low 73 | |
| Landslide | 274 of 274 | 14.6 | 47.9 | 94.7 | Relatively Low 11, Very Low 263 | |
| Lightning | 274 of 274 | 0.5 | 48.6 | 82.6 | Relatively High 6, Relatively Moderate 126, Relatively Low 135, Very Low 7 | National data give a county-wide or coarse (49 km grid or NWS zone) frequency for this hazard, so they cannot show members' hazard differing. The tract range above mostly reflects where buildings and people are. Confirm locally. |
| Strong Wind | 274 of 274 | 6.0 | 40.9 | 75.0 | Relatively Moderate 43, Relatively Low 222, Very Low 9 | National data give a county-wide or coarse (49 km grid or NWS zone) frequency for this hazard, so they cannot show members' hazard differing. The tract range above mostly reflects where buildings and people are. Confirm locally. |
| Tornado | 274 of 274 | 1.8 | 13.4 | 32.5 | Relatively Low 2, Very Low 272 | |
| Tsunami | 0 of 274 | Insufficient Data 274 | ||||
| Volcanic Activity | 0 of 274 | Not Applicable 274 | ||||
| Wildfire | 249 of 274 | 18.5 | 32.3 | 68.7 | Relatively Low 1, Very Low 248, No Rating 25 | |
| Winter Weather | 274 of 274 | 15.9 | 67.4 | 88.6 | Relatively High 38, Relatively Moderate 218, Relatively Low 15, Very Low 3 | National data give a county-wide or coarse (49 km grid or NWS zone) frequency for this hazard, so they cannot show members' hazard differing. The tract range above mostly reflects where buildings and people are. Confirm locally. |
Rated tracts only: No Rating (score 0.0), Not Applicable and Insufficient Data tracts are counted but not used for the minimum, median and maximum.
Source
FEMA, FEMA National Risk Index 1.20.0 (December 2025), county and census tract tables, version 1.20.0, pulled 2026-09-28, https://www.fema.gov/about/reports-and-data/openfema/nri/v120/NRI_Table_Counties.zip (download, 25 MB), https://www.fema.gov/about/reports-and-data/openfema/nri/v120/NRI_Table_CensusTracts.zip (download, 635 MB)
Per-member block (Starter, confirm locally)
| Member | Type | Plan status | Repetitive lossFMA RL and SRL (44 CFR 77.2); repeat-flood, any definition | Public Assistance matchedfederal share obligated, nominal dollars | Event records naming this placeall years; since the member's plan | Notes |
|---|---|---|---|---|---|---|
| Fairfax County | County | Approved, expires 2028-02-22 | FMA RL 3, SRL 7; any 100 | $108,832,982.62 | 0; 0 | Includes $100,313,312.33 for declarations not counted as hazard incidents (DR-4512-VA). |
| Clifton town | Town | Approved, expires 2028-02-22 | FMA RL 0, SRL 0; any 1 | $71,863.03 | 31; 5 | |
| Herndon town | Town | Approved, expires 2028-02-22 | FMA RL 0, SRL 0; any 1 | $582,276.97 | 40; 3 | Includes $80,324.80 for declarations not counted as hazard incidents (DR-4512-VA). |
| Vienna town | Town | Approved, expires 2028-02-22 | FMA RL 0, SRL 0; any 0 | none found | 38; 2 |
Member rows are whole NFIP communities and need not add up to the county total: a community that extends into another county is counted in full on each member row, while the county table counts only its part in this county.
School districts and special districts get a plan clock row only.
Sources
FEMA, OpenFEMA HazardMitigationPlanStatuses v1, version 2026-09-26T121003Z, pulled 2026-09-28, https://www.fema.gov/api/open/v1/HazardMitigationPlanStatuses (API)
FEMA, OpenFEMA NfipMultipleLossProperties v1, version 2026-08-04T164045Z, pulled 2026-09-28, https://www.fema.gov/api/open/v1/NfipMultipleLossProperties (API)
FEMA, OpenFEMA PublicAssistanceFundedProjectsSummaries v1, version 2026-09-26T151157Z, pulled 2026-09-28, https://www.fema.gov/api/open/v1/PublicAssistanceFundedProjectsSummaries (API)
NOAA NCEI, NOAA NCEI Storm Events Database, details files (csvfiles v1.0), version c20260918, pulled 2026-09-28, https://www.ncei.noaa.gov/pub/data/swdi/stormevents/csvfiles/
Supports B2-a and B2-b: assets and impacts
Local data required
County-level starter. The plan must describe impacts for each participant and its own assets.
- Critical facilities and lifelines per hazard
- A problem statement per participant per hazard
- Changes in development in hazard-prone areas since the last approval, or a statement of none (E1-a)
- Future assets
County-level starter: exposure, expected annual loss and damage since the plan
| Hazard | Building exposuremodeled dollars | Agriculture exposuremodeled dollars | Population exposedpeople | EAL buildingsmodeled dollars per year | EAL agriculturemodeled dollars per year | EAL population equivalencestatistical value of life and injury, $13.7M per life, not property damage | EAL as % of exposurebuildings; agriculture where noted | Storm Events damage since 2023-02-23county-coded records, property plus crops, nominal dollars | Zone-level damage since planproperty plus crops, reported for the zone | Public Assistance since plannominal dollars; see note | Note |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Avalanche | Not Applicable in NRI for this county | ||||||||||
| Coastal Flooding | $2,800,941,823 | 14,428 | $228,044 | $2,017 | 0.00814% | ||||||
| Cold Wave | $239,078,572,933 | $1,601,097 | 1,148,223 | $245,840 | $574 | $5,651,965 | 0.000103% | ||||
| Drought | $928,324 | $46,917 | 5.05% (agriculture) | NRI has no building exposure for this hazard; agriculture shown | |||||||
| Earthquake | $396,728,153,070 | 1,150,309 | $7,784,347 | $3,286,138 | 0.00196% | ||||||
| Hail | $239,078,583,329 | $1,601,097 | 1,148,223 | $4,017,135 | $168 | $7,700 | 0.00168% | ||||
| Heat Wave | $239,078,572,933 | $1,601,097 | 1,148,223 | $952 | $11 | $12,528,360 | under 0.0001% | $0 | |||
| Hurricane | $239,035,564,646 | $1,601,097 | 1,147,911 | $17,478,888 | $5,009 | $519,842 | 0.00731% | ||||
| Ice Storm | $237,153,933,026 | 1,138,481 | $571,426 | $45,935 | 0.000241% | ||||||
| Inland Flooding | $238,955,987,438 | $201,184 | 12,797 | $152,745,731 | $14,141 | $1,960,504 | n/a (see note) | $0 | NRI counts the full building value of any census block with some flood loss; this is not the value of buildings in the floodplain. Use local FIRM overlays for B2-a/B2-b. EAL as % of exposure: n/a. | ||
| Landslide | $5,977,166,273 | 26,879 | $10,107 | $265 | 0.000169% | ||||||
| Lightning | $239,078,583,329 | 1,148,223 | $219,259 | $3,673,265 | under 0.0001% | ||||||
| Strong Wind | $239,078,583,329 | $1,601,097 | 1,148,223 | $1,281,537 | $12,237 | $3,014,462 | 0.000536% | $3,638,000 | $0 | ||
| Tornado | $239,078,583,329 | $1,601,097 | 1,148,223 | $954,406 | $37 | $968,938 | 0.000399% | ||||
| Tsunami | NRI publishes no building exposure for this county | ||||||||||
| Volcanic Activity | Not Applicable in NRI for this county | ||||||||||
| Wildfire | $14,983,554,476 | $205,931 | 100,528 | $21,583 | under $1 | $2,783 | 0.000144% | ||||
| Winter Weather | $239,078,572,933 | $1,601,097 | 1,148,223 | $224,918 | under $1 | $1,594,150 | under 0.0001% | $0 | none found (1 declaration) |
Totals since 2023-02-23 (Storm Events through 2026-06-30): 154 county-coded records, 142 with a damage value recorded (including $0), $3,638,000; 23 zone-level records, 9 with a damage value recorded (including $0), $0 reported for the zone; Public Assistance on counted declarations none found (1 declaration, 0 with PA).
Total = buildings + agriculture + population equivalence; FEMA values each expected death (or 10 injuries) at $13.7 million (2024 dollars).
FEMA does not split Public Assistance by hazard. A declaration mapped to several hazards is listed under each of them with its full amount, so the per-hazard column must not be added up; the unit total counts each declaration once.
Dollars are nominal (as reported), labeled with the year; not adjusted for inflation.
Sources
FEMA, FEMA National Risk Index 1.20.0 (December 2025), county and census tract tables, version 1.20.0, pulled 2026-09-28, https://www.fema.gov/about/reports-and-data/openfema/nri/v120/NRI_Table_Counties.zip (download, 25 MB), https://www.fema.gov/about/reports-and-data/openfema/nri/v120/NRI_Table_CensusTracts.zip (download, 635 MB)
NOAA NCEI, NOAA NCEI Storm Events Database, details files (csvfiles v1.0), version c20260918, pulled 2026-09-28, https://www.ncei.noaa.gov/pub/data/swdi/stormevents/csvfiles/
NOAA National Weather Service, NWS county-public forecast zones correlation file, version bp03mr20 to bp16ap26 (11 files; newest bp16ap26), pulled 2026-09-28, https://www.weather.gov/gis/ZoneCounty
FEMA, OpenFEMA DisasterDeclarationsSummaries v2, version 2026-09-27T010817Z, pulled 2026-09-28, https://www.fema.gov/api/open/v2/DisasterDeclarationsSummaries (API)
FEMA, OpenFEMA PublicAssistanceFundedProjectsSummaries v1, version 2026-09-26T151157Z, pulled 2026-09-28, https://www.fema.gov/api/open/v1/PublicAssistanceFundedProjectsSummaries (API)
FEMA, OpenFEMA HazardMitigationPlanStatuses v1, version 2026-09-26T121003Z, pulled 2026-09-28, https://www.fema.gov/api/open/v1/HazardMitigationPlanStatuses (API)
Supports B2-a: context
County context
| Measure | Value |
|---|---|
| Population | 1,148,223 |
| Building value (total, not at risk) | $239,078,583,329 |
| Agriculture value (total, not at risk) | $1,601,097 |
| NRI risk rating (all hazards) | Relatively High |
| Expected annual loss, buildings and agriculture, all hazards | $185,863,267 |
| Expected annual loss, population equivalence, all hazards (NRI values each statistical life at $13.7M; a modeled value of expected deaths and injuries, not property damage) | $33,256,323 |
| Social vulnerability rating | Very Low |
| Community resilience rating | Relatively Moderate |
| NRI version | December 2025 |
FEMA's all-hazard expected annual loss total adds buildings, agriculture and population equivalence; the two parts are shown separately so the property figure is not read as including the statistical value of life.
Source
FEMA, FEMA National Risk Index 1.20.0 (December 2025), county and census tract tables, version 1.20.0, pulled 2026-09-28, https://www.fema.gov/about/reports-and-data/openfema/nri/v120/NRI_Table_Counties.zip (download, 25 MB), https://www.fema.gov/about/reports-and-data/openfema/nri/v120/NRI_Table_CensusTracts.zip (download, 635 MB)
Supports B2-c: repetitive loss
Repetitive loss in this county, both definitions
| Definition | Properties | Severe repetitive loss | Properties |
|---|---|---|---|
| Repetitive loss, FMA definition (44 CFR 77.2) | 3 | Severe repetitive loss, FMA definition (44 CFR 77.2) | 7 |
| Repetitive loss, NFIP insurance definition | 97 | Severe repetitive loss, NFIP insurance definition | 0 |
Your state NFIP coordinator's list may use the NFIP insurance definition, so its counts can be higher.
Sources
FEMA, OpenFEMA NfipMultipleLossProperties v1, version 2026-08-04T164045Z, pulled 2026-09-28, https://www.fema.gov/api/open/v1/NfipMultipleLossProperties (API)
FEMA, OpenFEMA HazardMitigationPlanStatuses v1, version 2026-09-26T121003Z, pulled 2026-09-28, https://www.fema.gov/api/open/v1/HazardMitigationPlanStatuses (API)
Repeat-flood properties: county and state-level rows
| Scope | RL, FMAproperties | SRL, FMAproperties | RL, NFIPproperties | SRL, NFIPproperties | Any categoryproperties | Mitigatedproperties | Currently insuredproperties |
|---|---|---|---|---|---|---|---|
| County total | 3 | 7 | 97 | 0 | 103 | 6 | 33 |
| HERNDON, TOWN OF | 0 | 0 | 1 | 0 | 1 | 0 | 1 |
| CLIFTON, TOWN OF | 0 | 0 | 1 | 0 | 1 | 0 | 1 |
| FAIRFAX COUNTY * | 3 | 7 | 94 | 0 | 100 | 6 | 31 |
| Unknown (community ID Unknown in FEMA data) | 0 | 0 | 1 | 0 | 1 | 0 | 0 |
| State level, not in this county: county not reported | 0 | 0 | 4 | 0 | 4 | 0 | 0 |
Sources
FEMA, OpenFEMA NfipMultipleLossProperties v1, version 2026-08-04T164045Z, pulled 2026-09-28, https://www.fema.gov/api/open/v1/NfipMultipleLossProperties (API)
FEMA, OpenFEMA HazardMitigationPlanStatuses v1, version 2026-09-26T121003Z, pulled 2026-09-28, https://www.fema.gov/api/open/v1/HazardMitigationPlanStatuses (API)
Repeat-flood properties by plan member (NFIP community)
| Member | NFIP community ID | RL, FMAproperties | SRL, FMAproperties | RL, NFIPproperties | SRL, NFIPproperties | Any categoryproperties | Mitigatedproperties | Currently insuredproperties | Note |
|---|---|---|---|---|---|---|---|---|---|
| Fairfax County | 515525 | 3 | 7 | 94 | 0 | 100 | 6 | 31 | |
| Clifton town | 510186 | 0 | 0 | 1 | 0 | 1 | 0 | 1 | |
| Herndon town | 510052 | 0 | 0 | 1 | 0 | 1 | 0 | 1 | |
| Vienna town | 510053 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
Per-member types: XLSX sheet 'B2-c Members'.
Member rows are whole NFIP communities and need not add up to the county total: a community that extends into another county is counted in full on each member row, while the county table counts only its part in this county.
Sources
FEMA, OpenFEMA NfipMultipleLossProperties v1, version 2026-08-04T164045Z, pulled 2026-09-28, https://www.fema.gov/api/open/v1/NfipMultipleLossProperties (API)
FEMA, OpenFEMA HazardMitigationPlanStatuses v1, version 2026-09-26T121003Z, pulled 2026-09-28, https://www.fema.gov/api/open/v1/HazardMitigationPlanStatuses (API)
County repeat-flood properties by occupancy group
| Occupancy group | RL, FMAproperties | SRL, FMAproperties | RL, NFIPproperties | SRL, NFIPproperties | Any categoryproperties | Mitigatedproperties | Currently insuredproperties |
|---|---|---|---|---|---|---|---|
| single-family residential | 3 | 7 | 92 | 0 | 98 | 6 | 32 |
| 2 to 4 unit residential | 0 | 0 | 4 | 0 | 4 | 0 | 1 |
| other residential | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| non-residential | 0 | 0 | 1 | 0 | 1 | 0 | 0 |
| not reported | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
Institutional properties cannot be separated in this data: FEMA's occupancy groups have no institutional class, so they fall in non-residential or other residential in the table by occupancy group.
Sources
FEMA, OpenFEMA NfipMultipleLossProperties v1, version 2026-08-04T164045Z, pulled 2026-09-28, https://www.fema.gov/api/open/v1/NfipMultipleLossProperties (API)
FEMA, OpenFEMA HazardMitigationPlanStatuses v1, version 2026-09-26T121003Z, pulled 2026-09-28, https://www.fema.gov/api/open/v1/HazardMitigationPlanStatuses (API)
FMA RL and FMA SRL are the Flood Mitigation Assistance definitions (44 CFR 77.2), the ones the FEMA Local Mitigation Planning Policy Guide cites; OpenFEMA's fmaRl field description omits the Increased Cost of Compliance clause of 44 CFR 77.2(i). NFIP repetitive loss (FEMA insurance definition, nfipRl) is 2 or more claims over $1,000 in 10 years and can drop to false when a property is mitigated. Also shown: NFIP severe repetitive loss, any category, mitigated and currently insured.
Your state NFIP coordinator's list may use the NFIP insurance definition, so its counts can be higher.
Counts are aggregates of FEMA's public NFIP Multiple Loss Properties file (as of 2026-08-02). No property is identified. County assignment is FEMA's geocode.
Counts may differ from your state NFIP coordinator's list, which is the source the Handbook names.
In this county 3 properties are FMA repetitive loss but not NFIP repetitive loss, and 97 properties are NFIP repetitive loss but not FMA repetitive loss.
Exact counts; no count suppression.
Sources
Every table above lists its own sources. The full list, for the plan's bibliography (FEMA review item A4-a):
- FEMA, OpenFEMA HazardMitigationPlanStatuses v1, version 2026-09-26T121003Z, pulled 2026-09-28, https://www.fema.gov/api/open/v1/HazardMitigationPlanStatuses (API)
- FEMA, OpenFEMA DisasterDeclarationsSummaries v2, version 2026-09-27T010817Z, pulled 2026-09-28, https://www.fema.gov/api/open/v2/DisasterDeclarationsSummaries (API)
- FEMA, OpenFEMA PublicAssistanceFundedProjectsSummaries v1, version 2026-09-26T151157Z, pulled 2026-09-28, https://www.fema.gov/api/open/v1/PublicAssistanceFundedProjectsSummaries (API)
- FEMA, OpenFEMA NfipMultipleLossProperties v1, version 2026-08-04T164045Z, pulled 2026-09-28, https://www.fema.gov/api/open/v1/NfipMultipleLossProperties (API)
- FEMA, FEMA National Risk Index 1.20.0 (December 2025), county and census tract tables, version 1.20.0, pulled 2026-09-28, https://www.fema.gov/about/reports-and-data/openfema/nri/v120/NRI_Table_Counties.zip (download, 25 MB), https://www.fema.gov/about/reports-and-data/openfema/nri/v120/NRI_Table_CensusTracts.zip (download, 635 MB)
- NOAA NCEI, NOAA NCEI Storm Events Database, details files (csvfiles v1.0), version c20260918, pulled 2026-09-28, https://www.ncei.noaa.gov/pub/data/swdi/stormevents/csvfiles/
- NOAA National Weather Service, NWS county-public forecast zones correlation file, version bp03mr20 to bp16ap26 (11 files; newest bp16ap26), pulled 2026-09-28, https://www.weather.gov/gis/ZoneCounty
- U.S. Census Bureau, Census 2024 Gazetteer, 2020 place by county, CT county-to-cousub crosswalk, version 2024-gazetteer, pulled 2026-09-28, https://www2.census.gov/geo/docs/maps-data/data/gazetteer/2024_Gazetteer/2024_Gaz_counties_national.zip, https://www2.census.gov/geo/docs/maps-data/data/gazetteer/2024_Gazetteer/2024_Gaz_cousubs_national.zip, https://www2.census.gov/geo/docs/maps-data/data/gazetteer/2024_Gazetteer/2024_Gaz_place_national.zip, https://www2.census.gov/geo/docs/maps-data/data/gazetteer/2024_Gazetteer/2024_Gaz_unsd_national.zip, https://www2.census.gov/geo/docs/maps-data/data/gazetteer/2024_Gazetteer/2024_Gaz_elsd_national.zip, https://www2.census.gov/geo/docs/maps-data/data/gazetteer/2024_Gazetteer/2024_Gaz_scsd_national.zip, https://www2.census.gov/geo/docs/reference/codes2020/national_place_by_county2020.txt, https://www2.census.gov/geo/docs/reference/ct_change/ct_cou_to_cousub_crosswalk.xlsx
OpenFEMA disclaimer
This product uses the Federal Emergency Management Agency's OpenFEMA API, but is not endorsed by FEMA. The Federal Government or FEMA cannot vouch for the data or analyses derived from these data after the data have been retrieved from the Agency's website(s).
Hazard Plain is an independent product built from public federal data. It is not a FEMA document and is not reviewed or endorsed by FEMA or any state agency.
Reuse, citation and corrections
Reuse and citation: Hazard Plain text and tables are licensed under Creative Commons Attribution 4.0 International (CC BY 4.0, https://creativecommons.org/licenses/by/4.0/); credit Hazard Plain and the release. The underlying federal data are public domain; OpenFEMA data are also subject to the OpenFEMA terms and conditions.
Cite this: Hazard Plain (2026). Fairfax County, VA: risk-assessment baseline packet, release 2026-10 (data as of 2026-09-28; County area 51059). Preview: automated baseline. Built from FEMA OpenFEMA, the FEMA National Risk Index and NOAA NCEI Storm Events; source versions in the packet's Sources list.
Corrections: to report an error, name the packet, the table and what your records show. Contact: to be added
Hazard Plain release 2026-10. As of 2026-09-28; Storm Events data through 2026-06-30. File hazard-plain_2026-10_VA_51059. Preview: automated baseline.