Hazard Plain Automated baseline

Grayson County, VA

Risk-assessment baseline packet

County FIPS:
51077
Release:
2026-10
Data as of:
2026-09-30
Storm Events data through:
2026-06-30

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.

Hazard Plain release 2026-10, as of 2026-09-30.

Summary

Plan status as of 2026-09-30: Approved, expires 2030-01-14. Plan: PDC 03 Mount Rogers Hazard Mitigation Plan (FEMA plan 110412), approved 2025-01-15.

Since the plan was approved on 2025-01-15: 2 new hazard declarations (2 incidents): DR-4863-VA (Severe Winter Storms and Flooding), EM-3631-VA (Severe Winter Storm).

NOAA Storm Events records since that date: 16 records (data through 2026-06-30).

Highest expected annual loss (FEMA National Risk Index, modeled total; see B1-a): Cold Wave ($2,503,910 a year), Inland Flooding ($2,365,265) and Drought ($207,978).

Repetitive-loss flood properties now: FMA RL 0, SRL 0 (44 CFR 77.2); any definition: 0.

The tables that follow are organized by the items of FEMA's Local Mitigation Plan Review Tool, Element B (B1-a to B2-c); each heading says which item its tables support.

Plan clock

Status:
Approved, expires 2030-01-14
Plan:
PDC 03 Mount Rogers Hazard Mitigation Plan (FEMA plan 110412)
Approved:
2025-01-15
Days to expiry:
1,202

What changed since your last plan (approved 2025-01-15)

New federal declarations:
2 new hazard declarations (2 incidents): DR-4863-VA (Severe Winter Storms and Flooding), EM-3631-VA (Severe Winter Storm)
Storm Events records since approval:
16 records (data through 2026-06-30)
Repetitive loss now:
FMA RL 0, SRL 0 (44 CFR 77.2); any definition: 0
Repeat-flood change:
this release sets the baseline count.

Sources: 1, 2, 4, 6 (numbered list at the end)

Plan status for every jurisdiction listed in this county

Source: 1

JurisdictionTypeStatusPlanApprovedExpiresDays to expirynegative = days since expiryUpdate underwayNotes
Grayson CountyCountyApproved, expires 2030-01-14PDC 03 Mount Rogers Hazard Mitigation Plan (FEMA plan 110412)2025-01-152030-01-141,202this jurisdiction approved 2025-02-13
Fries townTownApproved, expires 2030-01-14PDC 03 Mount Rogers Hazard Mitigation Plan (FEMA plan 110412)2025-01-152030-01-141,202this jurisdiction approved 2025-01-14
Independence townTownApproved, expires 2030-01-14PDC 03 Mount Rogers Hazard Mitigation Plan (FEMA plan 110412)2025-01-152030-01-141,202this jurisdiction approved 2025-06-10
Troutdale townTownPlan 110412 approved 2025-01-15, pending adoption here; not yet eligiblePDC 03 Mount Rogers Hazard Mitigation Plan (FEMA plan 110412), pending adoption here2025-01-15 by FEMA; not yet adopted here2030-01-14 once adoptedFEMA tracker shows a plan approvable pending adoptionNot yet eligible: adopt the approved plan.

Plan 110412 lists 18 other participants not on this page, 1 of them not covered by it yet (named in the Excel file).

State plan status and tribal plans in this state: see the state page.

Supports FEMA checklist item B1-a: hazard identification

Hazards NRI does not cover (local data needed)

  • 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)

Sources: 5, 6

Rank by EALHazardNRI risk ratingEAL ratingEAL buildingsmodeled dollars per yearEAL agriculturemodeled dollars per yearCost of expected deaths and injuriesFEMA's dollar value per year, not property damageEAL total (see note)modeled dollars per yearStorm Events records, 1996 to 2026-06-30countStorm Events coverage note
1Cold WaveRelatively ModerateRelatively Moderate$575$46,343$2,456,992$2,503,91010Includes 3 Frost/Freeze records (outside NRI's Cold Wave definition; counted in this table and in B1-d, not in the B1-e descriptor).
2Inland FloodingVery LowVery Low$2,318,395$33,824$13,047$2,365,26553
3DroughtRelatively LowRelatively Lown/a$207,978n/a$207,97826
4LightningRelatively LowRelatively Low$5,953n/a$195,714$201,6674
5TornadoVery LowVery Low$67,479$572$83,237$151,2883
6Strong WindRelatively LowRelatively Low$28,545$4,896$116,720$150,161172Includes 90 High Wind and 4 Strong Wind records (NOAA non-thunderstorm wind types, outside NRI's Strong Wind definition).
7EarthquakeVery LowVery Low$80,746n/a$28,188$108,934Storm Events does not record earthquakes.
8HurricaneVery LowVery Low$56,549$21,122$2,406$80,0760Declared 4 times; no Storm Events record of this type.
9LandslideRelatively ModerateRelatively Low$12,081n/a$35,192$47,2731
10Ice StormRelatively LowRelatively Low$28,819n/a$10,930$39,74910
11HailVery LowVery Low$12,892$3,856$22,252$39,00078
12WildfireVery LowVery Low$16,356$201$8,746$25,3030No recorded events in Storm Events since 1996 (data through 2026-06-30).
13Winter WeatherRelatively LowRelatively Low$2,184$34$16,293$18,51189
14AvalancheVery LowVery Lowunder $1n/a$256$2560No recorded events in Storm Events since 1996 (data through 2026-06-30).
15Heat WaveNo RatingNo Expected Annual Losses$0$0$0$00No recorded events in Storm Events since 1996 (data through 2026-06-30).

Total = buildings + agriculture + population equivalence; FEMA values each expected death (or 10 injuries) at $13.7 million (2024 dollars).

NRI risk rating combines expected annual loss with social vulnerability and community resilience; EAL rating rates expected annual loss alone. Both compare this county with all U.S. counties.

Local data needed: state and local wildfire records (Storm Events records this hazard only in part).

Not applicable to this county per NRI, with no federal declaration and no Storm Events record since 1996: coastal flooding, tsunami and volcanic activity. That is the evidence for leaving them out of the plan.

The state hazard mitigation plan also lists hazards for this county; FEMA asks the plan to explain any hazard it leaves out.

Supports FEMA checklist item B1-b: hazard location

Affects the whole county (national data give no location within it): Cold Wave, Drought, Hail, Heat Wave, Ice Storm, Lightning, Strong Wind and Winter Weather.

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.

Hazards that vary within the county: highest-rated census tracts

Source: 5

HazardHighest-rated census tractsNRI risk rating, score 0 to 100
Avalanchetract 602.02 (Very Low, 31.6); tract 602.01 (Very Low, 30.9); tract 601.01 (Very Low, 30.5)
Earthquaketract 602.01 (Relatively Low, 59.0); tract 602.02 (Relatively Low, 57.9); tract 601.02 (Relatively Low, 43.5)
Hurricanetract 602.02 (Relatively Low, 61.7); tract 602.01 (Relatively Low, 59.4); tract 601.02 (Relatively Low, 59.3)
Landslidetract 602.02 (Relatively Moderate, 98.7); tract 602.01 (Relatively Moderate, 98.3); tract 603 (Relatively Moderate, 98.2)
Tornadotract 602.01 (Relatively Low, 46.7); tract 601.02 (Relatively Low, 44.8); tract 602.02 (Relatively Low, 44.4)
Wildfiretract 602.02 (Relatively Low, 84.4); tract 601.02 (Relatively Low, 84.3); tract 602.01 (Relatively Low, 80.1)

Up to 3 census tracts per hazard, highest National Risk Index rating first, then highest score; a tract number is the Census tract number (for example 602.02 is Census Tract 602.02). FEMA's Resilience Analysis and Planning Tool maps the National Risk Index for every tract: https://www.fema.gov/emergency-managers/practitioners/resilience-analysis-and-planning-tool

Supports FEMA checklist item B1-c: hazard extent

Extent: scale, observed range and worst recorded event per hazard

Sources: 6, 7

HazardScaleRecordscount and yearsObserved rangeWorst recorded eventMost damaging (when different)How it applies to jurisdictionsNote
Avalanchenone (count and damage only)0Physical measure: in event narratives only (local data needed).
Cold/Wind Chill, Extreme Cold/Wind Chillwind chill7 records, 1996 to 2026 (7 zone-level)1 day to 5 days (median 1 day); 7 with a recorded value5 consecutive days, 1996-03-08 to 1996-03-12, zone-levelCountywide (zone-level records).Wind chill: in event narratives only (local data needed).
Frost/Freeze (outside NRI's Cold Wave definition)crop damage3 records, 2001 to 2012 (3 zone-level)No crop damage reported in 3 records.Countywide (zone-level records).Temperature: in event narratives only (local data needed).
DroughtU.S. Drought Monitor scale (D0 to D4)26 records, 1998 to 2026 (26 zone-level)15 days to 225 days (median 67 days); 8 with a recorded value225 days (about 7.4 months), 2007-08-14 to 2008-03-25, a run of 8 consecutive Storm Events drought records, zone-levelDrought, 2007-09-01, $0 property; $7,000,000 crops, reported for the zone (2007 dollars)Countywide (zone-level records).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.
EarthquakeModified Mercalli (local data)0Storm Events does not record earthquakes; the USGS earthquake catalog is the source.
Hailhail size (inches)80 records, 1984 to 20240.75 in to 1.75 in (median 0.88 in); 80 with a recorded value1.75 in hail, 2021-03-27; same size also recorded on 2010-05-15, 2011-05-11Hail, 2007-06-24, $4,000 property; $0 crops (2007 dollars)Event records naming jurisdictions in the plan: Independence town (21 records), Fries town (14 records), Troutdale town (1 record).
Excessive Heat, Heatheat index (in event narratives)0Heat index: in event narratives only (local data needed).
Hurricane, Tropical Storm, Tropical DepressionSaffir-Simpson0Storm Events files every zone of a storm's episode under the storm's type; flooding from the storm is filed as Flood or Flash Flood records.
Ice StormSperry-Piltz ice scale (local data)10 records, 1998 to 2018 (10 zone-level)Ice Storm, 2007-12-15, $15,000 property; $0 crops (2007 dollars); NWS zone VAZ015Countywide (zone-level records).Ice thickness: in event narratives only (local data needed).
Flash Flood, Flood, Lakeshore Flooddamage and flood days (flood depth: FIRM)53 records, 1996 to 2024 (2 zone-level)Flash Flood, 2024-09-27, $23,000,000 property; $38,000,000 crops (2024 dollars), 1 direct deathEvent records naming jurisdictions in the plan: Fries town (8 records), Independence town (6 records). Zone-level records (2) apply countywide.Flood depth: see the FEMA Flood Insurance Rate Map. Storm Events damage is often $0 or blank for floods, major ones included; FEMA Public Assistance by declaration (B1-d) shows which floods cost the most.
Debris Flownone (count and damage only)1 record, 2015No damage reported in 1 record.No event record names a jurisdiction in the plan.Physical measure: in event narratives only (local data needed).
Lightningannualized frequency (the measure FEMA's Local Mitigation Planning Handbook names)4 records, 1996 to 2011Lightning, 2005-05-10, $1,000 property; crops not reported (2005 dollars)Event records naming jurisdictions in the plan: Independence town (1 record).Storm Events lists lightning with damage or casualties; physical measure in event narratives only (local data needed).
High Wind and Strong Wind (outside NRI's Strong Wind definition)wind speed (kt and mph)94 records, 1999 to 2025 (94 zone-level)35 kt (40 mph) to 65 kt (75 mph) (median 52 kt (60 mph)); 83 with a recorded value65 kt (75 mph) estimated sustained, High Wind, 2003-02-22; NWS zone VAZ015High Wind, 2024-09-27, $15,500,000 property; $60,000,000 crops, reported for the zone (2024 dollars) (as recorded; larger than this county's annual agriculture value in the National Risk Index (the county or state extension service keeps crop loss records))Countywide (zone-level records).
Thunderstorm Windwind speed (kt and mph)84 records, 1962 to 202550 kt (58 mph) to 70 kt (81 mph) (median 50 kt (58 mph)); 72 with a recorded value70 kt (81 mph) estimated gust, Thunderstorm Wind, 2024-09-25; same speed and measurement basis also recorded on 2005-07-15, 2011-09-02Thunderstorm Wind, 2011-09-02, $55,000 property; crops not reported (2011 dollars)Event records naming jurisdictions in the plan: Independence town (12 records), Fries town (7 records), Troutdale town (4 records).
TornadoEnhanced Fujita (Fujita before Feb 2007)4 records, 1959 to 2022F/EF0 to F/EF1 (median F/EF1); 4 with a recorded valueEF1 tornado, 2017-10-23, 0.57 mi within this county, 150 yd wide, $100,000 property; crops not reported (2017 dollars)No event record names a jurisdiction in the plan.Before 1996 a tornado is listed once, under the county where it began, with its whole path's rating and length; from 1996 on, each county lists its own segment. Length is not used to rank tornadoes (see Methods).
Wildfireacres burned (local data)0Acres burned: in event narratives only (local data needed).
Winter Storm, Heavy Snow, Blizzard, Lake-Effect Snow, Winter Weather, Sleetnone in data (snowfall: local data)89 records, 1996 to 2026 (88 zone-level)Winter Storm, 2021-02-01, $10,000 property; $0 crops (2021 dollars); NWS zone VAZ015No event record names a jurisdiction in the plan. Zone-level records (88) apply countywide.Snow depth: in event narratives only (local data needed).

Storm Events records are more complete after 1996; before 1996 only Tornado (from 1950), Hail and Thunderstorm Wind (from 1955) exist. Zone-level records whose zone no NWS zone-county file places in this county (mostly before 2020) are not counted here (the Methods page explains the zone matching).

Dollars are nominal (as reported), labeled with the year; not adjusted for inflation.

Supports FEMA checklist item B1-d: previous occurrences

Federal declarations for this county: 21 declarations covering 16 separate hazard incidents counted in this packet (declarations for the same incident count once; non-natural and evacuation-only declarations are not counted).

Federal disaster declarations for this county

Sources: 1, 2, 3

DeclaredIncident beganFEMA numberTypeTitleMapped hazardCounty Public Assistancefederal share obligated, nominal dollarsFlagsNotes
2026-01-232026-01-22EM-3631-VAEmergencySevere Winter StormWinter Weatherno Public Assistance recordednew since last plan; within last 5 years
2025-04-042025-02-10DR-4863-VAMajor disasterSevere Winter Storms and FloodingInland Flooding; Tornado; Winter Weather$18,011.67new since last plan; within last 5 years
2024-10-012024-09-25DR-4831-VAMajor disasterTropical Storm HeleneHurricane$404,875.42in the 12 months before plan approval; within last 5 years
2024-09-292024-09-25EM-3621-VAEmergencyPost-Tropical Cyclone HeleneHurricaneno Public Assistance recordedin the 12 months before plan approval; within last 5 yearssame incident as DR-4831
2020-04-022020-01-20DR-4512-VAMajor disasterCOVID-19 PandemicNon-natural, not countedno Public Assistance recorded
2020-03-132020-01-20EM-3448-VAEmergencyCOVID-19Non-natural, not countedno Public Assistance recordedsame incident as DR-4512
2018-12-182018-10-09DR-4411-VAMajor disasterTropical Storm MichaelHurricane$3,642.66
2018-10-152018-09-08DR-4401-VAMajor disasterHurricane FlorenceHurricane$18,381.40
2018-09-112018-09-13EM-3403-VAEmergencyHurricane FlorenceHurricaneno Public Assistance recordedsame incident as DR-4401
2012-10-292012-10-26EM-3359-VAEmergencyHurricane SandyHurricaneno Public Assistance recorded
2010-02-162009-12-18DR-1874-VAMajor disasterSevere Winter Storm and SnowstormWinter Weatherno Public Assistance recorded
2005-09-122005-08-29EM-3240-VAEmergencyHurricane Katrina EvacuationHurricane: evacuation support, not a local hazard event; not countedno Public Assistance recorded
2000-02-282000-01-25DR-1318-VAMajor disasterSevere Winter StormsWinter Weatherno Public Assistance recorded
1996-01-271996-01-19DR-1098-VAMajor disasterFlooding, High Winds, and Wind Driven RainInland Flooding (primary); also designated: Strong Windno Public Assistance recorded
1996-01-131996-01-06DR-1086-VAMajor disasterBlizzard of 96 (Severe Snow Storm)Winter Weatherno Public Assistance recorded
1994-03-101994-02-08DR-1014-VAMajor disasterSevere Ice Storms, FloodingWinter Weather (primary); also designated: Inland Floodingno Public Assistance recorded
1993-03-251993-03-13EM-3112-VAEmergencySevere Winter StormWinter Weatherno Public Assistance recorded
1977-11-121977-11-12DR-543-VAMajor disasterSevere Storms & FloodingInland Floodingno Public Assistance recorded
1977-07-231977-07-23EM-3046-VAEmergencyDroughtDroughtno Public Assistance recorded
1977-04-071977-04-07DR-530-VAMajor disasterSevere Storms & FloodingInland Floodingno Public Assistance recorded
1976-10-151976-10-15EM-3018-VAEmergencyDroughtDroughtno Public Assistance recorded

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.

Statewide declarations

Source: 2

DeclaredIncident beganFEMA numberTypeTitleMapped hazard
1963-03-211963-03-21DR-149-VAMajor disasterFloodsInland Flooding
1962-03-091962-03-09DR-123-VAMajor disasterSevere Storms, High Tides & FloodingInland Flooding (primary); also designated: Coastal Flooding
1957-02-011957-02-01DR-68-VAMajor disasterFloodsInland Flooding

FEMA recorded these with designated area Statewide and no county, so they are listed on every county page in the state and not counted with county rows. Local data needed: whether each one affected this county.

Previous occurrences by hazard, with explicit no-event rows

Sources: 2, 6, 7

HazardStorm Events records, all years on file(years in the Period column)Since plan approvalrecordsIn the 12 months before plan approvalrecordsLast 5 yearsrecordsDeclared incidents, all yearsseparate disastersDeclared since approvalseparate disastersPeriodStatement
Avalanche0000001996 to 2026-06-30No recorded events, 1996 to 2026-06-30, NOAA NCEI Storm Events
Cold Wave10102001996 to 2026-06-30Includes 3 Frost/Freeze records.
Drought26305201996 to 2026-06-30
Earthquake000000Storm Events does not record earthquakes; the USGS earthquake catalog is the source.
Hail80011001955 to 2026-06-30
Heat Wave0000001996 to 2026-06-30No recorded events, 1996 to 2026-06-30, NOAA NCEI Storm Events
Hurricane0000401996 to 2026-06-30No Storm Events records of this type; 4 federal declared incidents (see declarations table)
Ice Storm10000001996 to 2026-06-30
Inland Flooding5301212511996 to 2026-06-30
Landslide1000001996 to 2026-06-30
Lightning4000001996 to 2026-06-30
Strong Wind17881031101955 to 2026-06-30Includes 90 High Wind and 4 Strong Wind records.
Tornado4001111950 to 2026-06-30
Wildfire0000001996 to 2026-06-30No recorded events, 1996 to 2026-06-30, NOAA NCEI Storm Events
Winter Weather894311721996 to 2026-06-30

Notable Storm Events records

Sources: 1, 6, 7

DateEvent typeMagnitude or extentDamagenominal dollarsDeaths, injuriesdirect onlyLocationFlagsWhy listed
2024-09-27High Wind56 kt (64 mph) measured gust$15,500,000 property; $60,000,000 crops, reported for the zone (2024 dollars) (as recorded; larger than this county's annual agriculture value in the National Risk Index (the county or state extension service keeps crop loss records))0, 3NWS zone VAZ015 (GRAYSON), zone-levelin the 12 months before plan approval; within last 5 yearsdeaths or injuries recorded
2024-09-27Flash Flood$23,000,000 property; $38,000,000 crops (2024 dollars)1, 0WHITETOP to RUGBYin the 12 months before plan approval; within last 5 yearsdeaths or injuries recorded
2024-09-25Thunderstorm Wind70 kt (81 mph) estimated gust$15,000 property; $0 crops (2024 dollars)0, 0RUGBYin the 12 months before plan approval; within last 5 yearsB1-c worst recorded: Thunderstorm Wind
2021-03-27Hail1.75 in$0 property; $0 crops (2021 dollars)0, 0ELK CREEKB1-c worst recorded: Hail
2021-02-01Winter Storm$10,000 property; $0 crops, reported for the zone (2021 dollars)0, 0NWS zone VAZ015 (GRAYSON), zone-levelB1-c worst recorded: Winter Storm, Heavy Snow, Blizzard, Lake-Effect Snow, Winter Weather, Sleet
2017-10-23TornadoEF1, 0.57 mi within this county, 150 yd wide$100,000 property; crops not reported (2017 dollars)0, 0PROVIDENCEB1-c worst recorded: Tornado
2007-12-15Ice Storm$15,000 property; $0 crops, reported for the zone (2007 dollars)0, 0NWS zone VAZ015 (GRAYSON), zone-levelB1-c worst recorded: Ice Storm
2007-08-14Drought$0 property; $0 crops, reported for the zone (2007 dollars)0, 0NWS zone VAZ015 (GRAYSON), zone-levelB1-c worst recorded: Drought
2005-05-10Lightning$1,000 property; crops not reported (2005 dollars)0, 0INDEPENDENCEB1-c worst recorded: Lightning
2003-02-22High Wind65 kt (75 mph) estimated sustained$0 property; crops not reported, reported for the zone (2003 dollars)0, 0NWS zone VAZ015 (GRAYSON), zone-levelB1-c worst recorded: High Wind and Strong Wind
1998-06-24Lightningdamage not reported0, 3WHITETOPdeaths or injuries recorded
1996-03-08Cold/Wind Chillproperty not reported; $3,000 crops, reported for the zone (1996 dollars)0, 0NWS zone VAZ015 (GRAYSON), zone-levelB1-c worst recorded: Cold/Wind Chill, Extreme Cold/Wind Chill

The full list is in the Excel file, sheet "B1-d Storm Events history" (455 rows).

Location is the place NOAA recorded, as written in its data; it need not be a jurisdiction in this plan.

Local data needed: state-declared emergencies, from your state emergency management agency (federal data do not include them).

Tribal and special-area declarations in this state are listed on the state page.

Supports FEMA checklist item B1-e: probability of future events

Probability: FEMA annualized frequency and descriptor per hazard

Sources: 5, 6

HazardFEMA annualized frequency (modeled)unit per rowUnitIn plain termsDescriptorDescriptor basisNRI events or days in its record period (hail, wind and tornado are area-weighted, so can be fractional)NRI periodLocationNote
Avalanche0.01events per yearabout 1 in 100 yearsPossibleFEMA annualized frequency (modeled)01994 to 2023 (30 years)see B1-f0.01 is NRI's minimum avalanche frequency for a county in an avalanche susceptibility zone; NRI records no avalanche here, so the descriptor reflects the floor, not local events.
Cold Wave4.84event-days per yearabout 4.84 days per yearLikely (from Storm Events: 4 of 30 years)event-days in 4 of 30 years, 1996 to 2025 (13.3%)922005-11-12 to 2024-11-12 (19 years)countywide
Drought9.81event-days per yearabout 9.81 days per yearLikely (from Storm Events: 5 of 30 years)event-days in 5 of 30 years, 1996 to 2025 (16.7%)3992000 to 2025 (25.25 years; D3 and D4 only)countywide
Earthquake0.00152annual probability at a locationchance a given location in the county has at least minor-damage shaking in a year: 0.152%not shownmodeledsee B1-fNo descriptor (Storm Events does not record earthquakes).
Hail4.02events per yearabout 4.02 per yearHighly likelyFEMA annualized frequency (modeled)152.6 (modeled)1986 to 2023 (38 years)countywide
Heat Wave0event-days per yearnone modeledevent-days in 0 of 30 years, 1996 to 2025 (0%)02005-11-12 to 2024-11-12 (19 years)countywideNo Storm Events heat wave record, 1996 to 2025
Hurricane0.0279events per yearabout 1 in 36 yearsPossibleFEMA annualized frequency (modeled)61851 to 2024 (Atlantic)see B1-fNRI counts hurricane and tropical storm tracks passing within storm-force wind range; federal declarations are in B1-d.
Ice Storm0.611event-days per yearabout 0.611 days per yearLikely (from Storm Events: 9 of 30 years)event-days in 9 of 30 years, 1996 to 2025 (30%)421946-12-31 to 2014-02-12 (67 years)countywide
Inland Flooding1.25event-days per yearabout 1.25 days per yearLikely (from Storm Events: 17 of 30 years)event-days in 17 of 30 years, 1996 to 2025 (56.7%)351996 to 2023 (28 years)see B1-f
Landslide1.27events per year (modeled)about 1.27 per yearHighly likelyFEMA annualized frequency (modeled)not shownmodeledsee B1-f
Lightning47.6days per year with a strikeabout 47.6 days per yearHighly likelyFEMA annualized frequency (modeled)not shown1995 to 2023 (29 years; CONUS)countywide
Strong Wind2.61events per yearabout 2.61 per yearHighly likelyFEMA annualized frequency (modeled)1001986 to 2023 (38 years)countywide
Tornado0.093events per yearabout 1 in 11 yearsPossibleFEMA annualized frequency (modeled)not shown1950 to 2023 (EF2+); 1986 to 2023 (EF0-1)see B1-f
Wildfire0.00137annual probability at a locationchance a given location in the county burns in a year: 0.137%Storm Events records in 0 of 30 years, 1996 to 2025 (0%)not shownmodeledsee B1-fNo descriptor: no Storm Events record 1996 to 2025
Winter Weather19.3event-days per yearabout 19.3 days per yearHighly likely (from Storm Events: 28 of 30 years)event-days in 28 of 30 years, 1996 to 2025 (93.3%)3662005-11-12 to 2024-11-12 (19 years)countywide

FEMA annualized frequency (modeled) is the National Risk Index v1.20 (December 2025) estimate of how often a hazard affects this county in a year; it is not recorded events divided by years, and its unit differs by hazard (events, event-days, or days with a lightning strike per year). For earthquake, wildfire, coastal flooding and tsunami the value is the chance (or number of events) at a location in the county, not across the county, so no "1 in N years" is given and the descriptor comes from Storm Events where it has a record (none for earthquake). The Methods page gives each hazard's method, from FEMA's National Risk Index Technical Documentation v1.20.

Where NRI gives event-days, the descriptor comes from the share of years with a Storm Events record; NRI's source records more events, so the two differ.

Descriptor scale used in this packet (defined per unit)

Sources: 5, 6

UnitDescriptorDefinition
events per yearHighly likely1 or more per year
events per yearLikelyabout once in 1 to 10 years
events per yearPossibleabout once in 10 to 100 years
events per yearUnlikelyless than once in 100 years
annual probabilityLikely10% to under 100% chance in a given year
annual probabilityPossible1% to under 10% chance in a given year
annual probabilityUnlikelyunder 1% chance in a given year
event-days (share of years)Highly likelyevent-days recorded in 90% or more of years
event-days (share of years)Likelyevent-days recorded in 10% to under 90% of years
event-days (share of years)Possibleevent-days recorded in some years but under 10% of years
lightning strike-daysHighly likelycloud-to-ground strikes on 1 or more days per year

Intensity bands: historical frequency (Storm Events)

Source: 6

HazardBandYearsEventscounty-coded recordsYears in periodEvents per yearevents / years
Hail1.00-1.99 in1996 to 202534301.13
Hail2.00 in+1996 to 20250300
Thunderstorm Wind (counted as NRI Strong Wind)50-64 kt1996 to 202566302.2
Thunderstorm Wind (counted as NRI Strong Wind)65 kt+1996 to 20256300.2
Thunderstorm Wind (counted as NRI Strong Wind)unmeasured or below 50 kt1996 to 20256300.2
TornadoEF0-11996 to 20253300.1
TornadoEF2-31996 to 20250300
TornadoEF4-51996 to 20250300
Tornadounrated (EFU)1996 to 20250300

The bands show how often events of each severity were recorded in this county, to profile how severe events have been (FEMA's probability item asks for the range of intensities).

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.

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 (https://resilience.climate.gov/).

Supports FEMA checklist item B1-f: hazards that vary across jurisdictions

Range of census tract risk within the county

Source: 5

HazardTractsrated of allNRI risk score, 0 to 100Tracts by rating
MinMedianMax
Avalanche4 of 529.730.731.6Very Low 4, Not Applicable 1
Cold Wave5 of 592.697.698.5Very High 4, Relatively High 1
Drought5 of 588.692.196.2Relatively Moderate 3, Relatively Low 2
Earthquake5 of 537.343.559.0Relatively Low 4, Very Low 1
Hail5 of 547.859.261.4Relatively Low 5
Heat Wave0 of 5No Rating 5
Hurricane5 of 552.859.361.7Relatively Low 5
Ice Storm5 of 554.072.179.9Relatively Moderate 3, Relatively Low 2
Inland Flooding5 of 530.558.170.1Relatively Moderate 3, Relatively Low 2
Landslide5 of 596.698.298.7Relatively Moderate 5
Lightning5 of 581.393.896.1Very High 1, Relatively High 4
Strong Wind5 of 560.174.880.0Relatively Moderate 5
Tornado5 of 534.744.446.7Relatively Low 5
Wildfire5 of 575.680.184.4Relatively Low 5
Winter Weather5 of 552.466.572.7Relatively Moderate 5

Drought: Agriculture is all of NRI's expected annual loss for this hazard in the county, so the tract range mostly reflects where crop and livestock value is.

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.

The score ranks a tract against all U.S. tracts (100 = highest). The rating is FEMA's category for the tract's risk value, computed differently, so the two can disagree.

Frequency data for cold wave, drought, hail, ice storm, lightning, strong wind and winter weather are county-wide or coarse (49 km grid or NWS zone), the same for every jurisdiction; the tract range mostly reflects where buildings and people are (crop and livestock value where a line above names agriculture).

Each jurisdiction (starting figures from federal data)

Sources: 1, 3, 4, 6

JurisdictionTypePlan statusRepetitive lossFMA RL and SRL (44 CFR 77.2); repeat-flood, any definitionPublic Assistance to this jurisdictionFEMA records matched by applicant name; federal share obligated, nominal dollarsEvent records naming this placeall years; since its plan
Grayson CountyCountyApproved, expires 2030-01-14FMA RL 0, SRL 0; any 0$125,874.220 total; 0 since its plan
Fries townTownApproved, expires 2030-01-14FMA RL 0, SRL 0; any 0$29,68729 total; 0 since its plan
Independence townTownApproved, expires 2030-01-14FMA RL 0, SRL 0; any 0$107,281.6640 total; 0 since its plan
Troutdale townTownPlan 110412 approved 2025-01-15, pending adoption here; not yet eligibleFMA RL 0, SRL 0; any 0no Public Assistance recorded5 total; no approved plan

Repetitive-loss counts are for whole NFIP communities, which can extend beyond this county (see the note in B2-c).

County Public Assistance in B1-d also includes applicants filed under the county that are not jurisdictions in this plan (for example state agencies, special districts and nonprofits), so the jurisdiction rows add up to less.

Supports FEMA checklist items B2-a and B2-b: vulnerability and potential impacts

Local data needed

The table below gives county-level starting figures; the plan describes impacts for each jurisdiction and its own assets.

  • Critical facilities and lifelines per hazard
  • A problem statement per jurisdiction 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

Sources: 1, 2, 3, 5, 6, 7

HazardBuilding exposuremodeled dollarsAgriculture exposuremodeled dollarsPopulation exposedpeopleEAL buildingsmodeled dollars per yearEAL agriculturemodeled dollars per yearCost of expected deaths and injuriesFEMA's dollar value per year, not property damageEAL as % of exposurebuildings; agriculture where notedStorm Events damage since 2025-01-15county-coded records, property plus crops, nominal dollarsZone-level damage since planproperty plus crops, reported for the zonePublic Assistance since plannominal dollars; see noteNote
Avalanche$119,219n/aunder 1under $1n/a$256under 0.0001%
Cold Wave$2,364,061,430$52,564,44815,333$575$46,343$2,456,992under 0.0001%$0
Droughtn/a$7,524,383n/an/a$207,978n/a2.76% (agriculture)NRI has no building exposure for this hazard; agriculture shown
Earthquake$3,944,597,761n/a15,333$80,746n/a$28,1880.00205%
Hail$2,364,061,430$52,564,44815,333$12,892$3,856$22,2520.000545%
Heat Wave$0$00$0$0$0building exposure is 0 in NRI
Hurricane$2,355,807,334$51,152,79415,267$56,549$21,122$2,4060.0024%
Ice Storm$2,362,572,107n/a15,326$28,819n/a$10,9300.00122%
Inland Flooding$2,361,551,095$2,785,443316$2,318,395$33,824$13,047n/a (see note)$18,011.67NRI 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.
Landslide$467,345,771n/a3,266$12,081n/a$35,1920.00259%
Lightning$2,364,061,430n/a15,333$5,953n/a$195,7140.000252%
Strong Wind$2,364,061,430$52,564,44815,333$28,545$4,896$116,7200.00121%$7,000$5,000Storm Events damage since the plan includes 1 zone-level High Wind record ($5,000): a NOAA non-thunderstorm wind type, outside NRI's Strong Wind definition.
Tornado$2,364,061,430$52,564,44815,333$67,479$572$83,2370.00285%$18,011.67
Wildfire$207,231,708$19,627,7024,343$16,356$201$8,7460.00789%
Winter Weather$2,364,061,430$52,564,44815,333$2,184$34$16,293under 0.0001%$0$18,011.67

Totals since 2025-01-15 (Storm Events through 2026-06-30): 3 county-coded records, 3 with a damage value recorded (including $0), $7,000; 13 zone-level records, 8 with a damage value recorded (including $0), $5,000 reported for the zone; Public Assistance: $18,011.67 on 2 counted declarations, 1 of them with Public Assistance.

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 does not add up to the total; the unit total counts each declaration once.

NRI computes earthquake exposure on its own basis, so it exceeds the county building value in B2-a.

Supports FEMA checklist item B2-a: vulnerability (county context)

County context

Source: 5

MeasureValue
Population15,333
Building value (total, not at risk)$2,364,061,430
Agriculture value (total, not at risk)$52,564,448
NRI risk rating (all hazards)Very Low
Expected annual loss, buildings and agriculture, all hazards$2,949,399
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)$2,989,974
Social vulnerability ratingRelatively High
Community resilience ratingVery Low
NRI versionDecember 2025

FEMA's all-hazard expected annual loss adds buildings, agriculture and population equivalence; this table gives the property part and the population-equivalence part as separate rows.

Social vulnerability: higher means people are more likely to be harmed and slower to recover. Community resilience: lower means the community is less able to recover. High social vulnerability and low resilience both raise the NRI risk rating.

Supports FEMA checklist item B2-c: repetitive loss properties

Repetitive loss in this county, both definitions

Sources: 1, 4

DefinitionPropertiesSevere repetitive lossProperties
Repetitive loss, FMA definition (44 CFR 77.2)0Severe repetitive loss, FMA definition (44 CFR 77.2)0
Repetitive loss, NFIP insurance definition0Severe repetitive loss, NFIP insurance definition0

The state NFIP coordinator's list, the source FEMA's Handbook names, often uses the NFIP insurance definition (second row).

Repeat-flood properties: county and state-level rows

Sources: 1, 4

ScopeRL, FMApropertiesSRL, FMApropertiesRL, NFIPpropertiesSRL, NFIPpropertiesAny categorypropertiesMitigatedpropertiesCurrently insuredproperties
County total0000000
Statewide, no county in FEMA's file0040400

The statewide row counts properties FEMA's file gives with no county in this state; they are listed for reference and are not in this county's counts.

Repeat-flood properties by jurisdiction in the plan (NFIP community)

Sources: 1, 4

JurisdictionNFIP community IDRL, FMApropertiesSRL, FMApropertiesRL, NFIPpropertiesSRL, NFIPpropertiesAny categorypropertiesMitigatedpropertiesCurrently insuredproperties
Grayson County5102430000000
Fries town5102150000000
Independence town5102380000000
Troutdale town5100510000000

Counts by occupancy group for each jurisdiction are in the Excel file, sheet "B2-c Jurisdictions".

Jurisdiction 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 jurisdiction row, while the county table counts only its part in this county.

County repeat-flood properties by occupancy group: 0 in every occupancy group.

Sources: 1, 4

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. NFIP repetitive loss (the FEMA insurance definition) is 2 or more claims over $1,000 in 10 years, and a property can leave that group once it is mitigated. Also shown: NFIP severe repetitive loss, any category, mitigated and currently insured. The Methods page gives the OpenFEMA field details.

Counts are aggregates of FEMA's public NFIP Multiple Loss Properties file (FEMA's data date 2026-08-02; file version 2026-08-04). No property is identified. County assignment is FEMA's geocode.

In this county 0 properties are FMA repetitive loss but not NFIP repetitive loss, and 0 properties are NFIP repetitive loss but not FMA repetitive loss.

Exact counts; no count suppression.

Sources

Tables cite these sources by number. The full list, for the plan's bibliography (FEMA review item A4-a):

  1. FEMA, OpenFEMA HazardMitigationPlanStatuses v1, version 2026-09-29T134039Z, pulled 2026-09-30, https://www.fema.gov/api/open/v1/HazardMitigationPlanStatuses (API)
  2. FEMA, OpenFEMA DisasterDeclarationsSummaries v2, version 2026-09-29T162832Z, pulled 2026-09-30, https://www.fema.gov/api/open/v2/DisasterDeclarationsSummaries (API)
  3. FEMA, OpenFEMA PublicAssistanceFundedProjectsSummaries v1, version 2026-09-29T150754Z, pulled 2026-09-30, https://www.fema.gov/api/open/v1/PublicAssistanceFundedProjectsSummaries (API)
  4. FEMA, OpenFEMA NfipMultipleLossProperties v1, version 2026-08-04T164045Z, pulled 2026-09-30, https://www.fema.gov/api/open/v1/NfipMultipleLossProperties (API)
  5. FEMA, FEMA National Risk Index 1.20.0 (December 2025), county and census tract tables, version 1.20.0, pulled 2026-09-30, 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)
  6. NOAA NCEI, NOAA NCEI Storm Events Database, details files (csvfiles v1.0), version c20260918, pulled 2026-09-30, https://www.ncei.noaa.gov/pub/data/swdi/stormevents/csvfiles/
  7. NOAA National Weather Service, NWS county-public forecast zones correlation file, version bp03mr20 to bp16ap26 (11 files; newest bp16ap26), pulled 2026-09-30, https://www.weather.gov/gis/ZoneCounty
  8. U.S. Census Bureau, Census 2024 Gazetteer, 2020 place by county, CT county-to-cousub crosswalk, version 2024-gazetteer, pulled 2026-09-30, 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 (used to match place names and codes; no table prints its values)

What this packet is and what the plan adds

This packet is the federal data for the plan's risk assessment, organized by the items of FEMA's Local Mitigation Plan Review Tool, Element B. Each section heading names the item its tables support; the plan and FEMA's review decide whether the item is met.

The plan adds what only the community has: local data on assets, critical facilities, development and each jurisdiction's impacts; local hazard history, including state-declared emergencies; the mitigation strategy; and adoption.

How the federal data are built: National Risk Index values are FEMA's model, not counts of events. Storm Events is more complete from 1996; zone-level records are placed by forecast zone, not by location in the county. Public Assistance for a jurisdiction is matched by applicant name. The Methods page gives every rule and the known edge cases.

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).

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). Grayson County, VA: risk-assessment baseline packet, release 2026-10 (data as of 2026-09-30; County FIPS 51077). Automated baseline. https://hazardplain.org/va/51077/ 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: [email protected]

Hazard Plain release 2026-10. As of 2026-09-30; Storm Events data through 2026-06-30. Automated baseline.