Hazard Plain Automated baseline

Charles County, MD

Risk-assessment baseline packet

County FIPS:
24017
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 2029-12-09. Plan: Charles County Hazard Mitigation Plan (FEMA plan 110057), approved 2024-12-10.

Since the plan was approved on 2024-12-10: 1 new hazard declaration (1 incident) and 43 NOAA Storm Events records; details under "What changed since your last plan".

Highest expected annual loss (FEMA National Risk Index, modeled total; see B1-a): Inland Flooding ($10,897,184 a year), Hurricane ($2,373,942) and Heat Wave ($2,284,904).

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 2029-12-09
Plan:
Charles County Hazard Mitigation Plan (FEMA plan 110057)
Approved:
2024-12-10
Days to expiry:
1,166

What changed since your last plan (approved 2024-12-10)

New federal declarations:
1 new hazard declaration (1 incident): EM-3634-MD (Severe Winter Storm)
Storm Events records since approval:
43 records (data through 2026-06-30)
Repetitive loss now:
FMA RL 2, SRL 6 (44 CFR 77.2); any definition: 36
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
Charles CountyCountyApproved, expires 2029-12-09Charles County Hazard Mitigation Plan (FEMA plan 110057)2024-12-102029-12-091,166
Indian Head townTownApproved, expires 2029-12-09Charles County Hazard Mitigation Plan (FEMA plan 110057)2024-12-102029-12-091,166this jurisdiction approved 2025-02-03
La Plata townTownApproved, expires 2029-12-09Charles County Hazard Mitigation Plan (FEMA plan 110057)2024-12-102029-12-091,166this jurisdiction approved 2025-02-25
Port Tobacco Village townTownPlan 110057 approved 2024-12-10, pending adoption here; not yet eligibleCharles County Hazard Mitigation Plan (FEMA plan 110057), pending adoption here2024-12-10 by FEMA; not yet adopted here2029-12-09 once adoptedFEMA tracker shows a plan approvable pending adoptionNot yet eligible: adopt the approved plan.

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
1Inland FloodingRelatively LowRelatively Low$10,838,034$9,133$50,017$10,897,18484
2HurricaneRelatively LowRelatively Moderate$2,238,081$61,666$74,196$2,373,9424
3Heat WaveRelatively ModerateRelatively Moderate$131$91$2,284,682$2,284,90479
4Strong WindRelatively ModerateRelatively High$725,610$49,711$1,134,472$1,909,793437Includes 10 High Wind and 15 Strong Wind records (NOAA non-thunderstorm wind types, outside NRI's Strong Wind definition).
5EarthquakeRelatively LowRelatively Low$907,546n/a$244,537$1,152,083Storm Events does not record earthquakes.
6DroughtRelatively ModerateRelatively Moderaten/a$965,097n/a$965,09712
7LightningRelatively ModerateRelatively High$29,967n/a$893,698$923,6657
8TornadoRelatively LowRelatively Low$601,956$335$182,376$784,66721
9HailRelatively LowRelatively Low$322,195$3,074$1,117$326,38687
10Cold WaveVery LowRelatively Low$23,853$13,714$259,943$297,51034Includes 22 Frost/Freeze records (outside NRI's Cold Wave definition; counted in this table and in B1-d, not in the B1-e descriptor).
11Coastal FloodingRelatively LowRelatively Low$272,501n/a$1,430$273,9318
12Winter WeatherRelatively ModerateRelatively Moderate$19,226$4$198,417$217,646117
13Ice StormRelatively LowRelatively Low$78,220n/a$4,127$82,3473
14WildfireVery LowVery Low$8,070$3$3,376$11,4490No recorded events in Storm Events since 1996 (data through 2026-06-30).
15LandslideVery LowVery Low$4,632n/a$82$4,7140No recorded events in Storm Events since 1996 (data through 2026-06-30).
TsunamiInsufficient DataInsufficient Datan/an/an/an/a0No 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, landslide and tsunami records (Storm Events records these hazards only in part).

Not applicable to this county per NRI, with no federal declaration and no Storm Events record since 1996: avalanche 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.

Coastal Flooding and 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
Earthquaketract 8509.01 (Relatively Low, 76.6); tract 8510.04 (Relatively Low, 70.3); tract 8506 (Relatively Low, 66.0)
Hurricanetract 8509.01 (Relatively Moderate, 80.2); tract 8507.09 (Relatively Moderate, 78.9); tract 8512 (Relatively Low, 78.4)
Landslidetract 8513.01 (Relatively Low, 92.2); tract 8514.02 (Relatively Low, 92.1); tract 8505 (Relatively Low, 91.0)
Tornadotract 8509.01 (Relatively Low, 41.9); tract 8507.09 (Relatively Low, 41.4); tract 8509.04 (Relatively Low, 38.9)
Tsunamino tract has a National Risk Index rating for this hazard
Wildfiretract 8514.02 (Relatively Low, 70.6); tract 8504 (Very Low, 66.9); tract 8512 (Very Low, 66.1)

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 8509.01 is Census Tract 8509.01). 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
Coastal Flood, Storm Surge/Tidenone in data (flood depth: FIRM)8 records, 1996 to 2015 (7 zone-level)Storm Surge/Tide, 1996-09-06, $1,600,000 property; $5,000 crops (1996 dollars)No event record names a jurisdiction in the plan. Zone-level records (7) apply countywide.Flood depth: see the FEMA Flood Insurance Rate Map.
Cold/Wind Chill, Extreme Cold/Wind Chillwind chill12 records, 1998 to 2026 (12 zone-level)1 day to 9 days (median 2 days); 11 with a recorded value9 consecutive days, 2026-01-23 to 2026-01-31, zone-levelCold/Wind Chill, 1998-03-11, property not reported; $2,500 crops (zone total, 1998 dollars)Countywide (zone-level records).
Frost/Freeze (outside NRI's Cold Wave definition)crop damage22 records, 2005 to 2021 (22 zone-level)No crop damage reported in 22 records.Countywide (zone-level records).
DroughtU.S. Drought Monitor scale (D0 to D4)12 records, 1998 to 2007 (12 zone-level)30 days to 140 days (median 43 days); 5 with a recorded value140 days (about 4.6 months), 1999-05-01 to 1999-09-17, a run of 5 consecutive Storm Events drought records, zone-levelDrought, 1998-11-01, property not reported; $1,670,000 crops (zone total, 1998 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)97 records, 1957 to 20260.75 in to 4.5 in (median 1 in); 97 with a recorded value4.5 in hail, 2002-04-28Hail, 2010-05-14, $750,000 property; crops not reported (2010 dollars)Event records naming jurisdictions in the plan: La Plata town (10 records), Indian Head town (1 record).
Excessive Heat, Heatheat index (in event narratives)79 records, 1996 to 2025 (79 zone-level)1 day to 8 days (median 2 days); 54 with a recorded value8 consecutive days, 2002-08-12 to 2002-08-19, zone-levelCountywide (zone-level records).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 DepressionSaffir-Simpson4 records, 1999 to 2020 (4 zone-level)Strongest recorded: Tropical Storm record, 2003-09-18 to 2003-09-19, $5,700,000 property; $10,000 crops (2003 dollars), 41 direct injuries (reported for the zone); NWS zone MDZ016Countywide (zone-level records).Storm 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)3 records, 2000 to 2021 (3 zone-level)No damage reported in 3 records.Countywide (zone-level records).
Flash Flood, Flood, Lakeshore Flooddamage and flood days (flood depth: FIRM)84 records, 1998 to 2025 (2 zone-level)Flash Flood, 1999-08-25, $200,000 property; crops not reported (1999 dollars)Event records naming jurisdictions in the plan: La Plata town (3 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)0
Lightningannualized frequency (the measure FEMA's Local Mitigation Planning Handbook names)7 records, 1996 to 2008Lightning, 2000-07-10, $50,000 property; crops not reported (2000 dollars)No event record names a jurisdiction in the plan.Storm Events lists lightning with damage or casualties.
High Wind and Strong Wind (outside NRI's Strong Wind definition)wind speed (kt and mph)25 records, 1997 to 2026 (25 zone-level)30 kt (35 mph) to 56 kt (64 mph) (median 50 kt (58 mph)); 16 with a recorded value56 kt (64 mph) measured gust, High Wind, 2026-02-07; same speed and measurement basis also recorded on 2000-01-13; NWS zone MDZ016High Wind, 2012-10-29, $969,190 property; $0 crops (zone total, 2012 dollars)Countywide (zone-level records).
Thunderstorm Windwind speed (kt and mph)457 records, 1958 to 202640 kt (46 mph) to 72 kt (83 mph) (median 52 kt (60 mph)); 379 with a recorded value72 kt (83 mph), measurement type not recorded, Thunderstorm Wind, 1994-06-21Thunderstorm Wind, 2023-07-29, $5,000,000 property; crops not reported (2023 dollars)Event records naming jurisdictions in the plan: La Plata town (37 records), Indian Head town (15 records).
TornadoEnhanced Fujita (Fujita before Feb 2007)28 records, 1973 to 2022F/EF0 to F/EF4 (median between F/EF0 and F/EF1); 28 with a recorded valueF4 tornado, 2002-04-28, 24 mi within this county, 650 yd wide, $114,000,000 property; crops not reported (2002 dollars), 1 direct death, 122 direct injuriesEvent records naming jurisdictions in the plan: La Plata town (6 records), Indian Head town (1 record).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).
Tsunaminone (count and damage only)0
Wildfireacres burned (local data)0
Winter Storm, Heavy Snow, Blizzard, Lake-Effect Snow, Winter Weather, Sleetnone in data (snowfall: local data)117 records, 1996 to 2026 (117 zone-level)Winter Storm, 2010-02-05, $5,000 property; crops not reported (2010 dollars); NWS zone MDZ016Countywide (zone-level records).

In event narratives only (local data needed): wind chill, temperature, heat index, ice thickness, acres burned and snow depth; any physical measure of debris flow, lightning and tsunami.

Storm Events records are more complete after 1996; before 1996 only Tornado (from 1950), Hail and Thunderstorm Wind (from 1955) exist. Zone-level records from zones that 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: 24 declarations covering 19 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
2026-01-242026-01-23EM-3634-MDEmergencySevere Winter StormWinter Weatherno Public Assistance recordednew since last plan; within last 5 years
2020-03-262020-01-20DR-4491-MDMajor disasterCOVID-19 PandemicNon-natural, not counted$311,832.38
2020-03-132020-01-20EM-3430-MDEmergencyCOVID-19Non-natural, not countedno Public Assistance recordedsame incident as DR-4491
2016-03-042016-01-22DR-4261-MDMajor disasterSevere Winter Storm and SnowstormWinter Weather$1,282,906.59
2012-11-202012-10-26DR-4091-MDMajor disasterHurricane SandyHurricane$121,981.27
2012-10-282012-10-26EM-3349-MDEmergencyHurricane SandyHurricaneno Public Assistance recordedsame incident as DR-4091
2012-08-022012-06-29DR-4075-MDMajor disasterSevere Storms and Straight-Line WindsStrong Wind$1,670,168.47
2011-10-052011-09-06DR-4038-MDMajor disasterRemnants of Tropical Storm LeeInland Flooding (primary); also designated: Hurricane$1,095,215.41
2011-09-162011-08-24DR-4034-MDMajor disasterHurricane IreneHurricane$6,081,970.84
2011-08-272011-08-26EM-3335-MDEmergencyHurricane IreneHurricaneno Public Assistance recordedsame incident as DR-4034
2010-05-062010-02-05DR-1910-MDMajor disasterSevere Winter Storms and SnowstormsWinter Weather$2,129,012.29
2010-02-192009-12-18DR-1875-MDMajor disasterSevere Winter Storm and SnowstormWinter Weather$801,614.94
2005-09-132005-08-29EM-3251-MDEmergencyHurricane Katrina EvacuationHurricane: evacuation support, not a local hazard event; not countedno Public Assistance recorded
2003-09-192003-09-18DR-1492-MDMajor disasterHurricane IsabelHurricane$3,803,760.88
2003-03-142003-02-14EM-3179-MDEmergencySnowWinter Weather$505,009.40
2002-05-012002-04-28DR-1409-MDMajor disasterTornadoTornado$2,950,815.18
2000-04-102000-01-25DR-1324-MDMajor disasterSevere Winter StormWinter Weather$386,863.59
1999-09-241999-09-16DR-1303-MDMajor disasterHurricane Floyd Major Disaster DeclarationsHurricane$973,591.26
1996-01-111996-01-06DR-1081-MDMajor disasterBlizzard of 96 (Severe Snow Storm)Winter Weatherno Public Assistance recorded
1994-03-161994-02-08DR-1016-MDMajor disasterSevere Winter Weather and Ice StormsWinter Weather (primary); also designated: Ice Stormno Public Assistance recorded
1993-03-161993-03-13EM-3100-MDEmergencySevere Snowfall & Winter StormWinter Weatherno Public Assistance recorded
1977-01-261977-01-26DR-524-MDMajor disasterIce ConditionsWinter WeatherPA not declared for this county
1975-10-041975-10-04DR-489-MDMajor disasterHeavy Rains & FloodingInland Floodingno Public Assistance recorded
1972-06-231972-06-23DR-341-MDMajor disasterTropical Storm AgnesInland Flooding (primary); also designated: Hurricaneno 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
1962-03-091962-03-09DR-127-MDMajor disasterSevere Storms, High Tides & FloodingInland Flooding (primary); also designated: Coastal 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.

Public Assistance filed under this county for declarations that do not list it: 1 row, $797,337.76

Sources: 2, 3

FEMA numberDeclaredTitleApplicantPA obligatedfederal share obligated, nominal dollars
DR-4583-MD2021-02-04Tropical Storm IsaiasSouthern Maryland Electric Cooperative$797,337.76

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.

Public Assistance not placed in any Maryland county: 1 row, $112,415.86; listed on the Maryland state page.

Source: 3

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
Coastal Flooding8000001996 to 2026-06-30
Cold Wave34203001996 to 2026-06-30Includes 22 Frost/Freeze records.
Drought12000001996 to 2026-06-30
Earthquake000000Storm Events does not record earthquakes; the USGS earthquake catalog is the source.
Hail971111001955 to 2026-06-30
Heat Wave79226001996 to 2026-06-30
Hurricane4000601996 to 2026-06-30
Ice Storm3000101996 to 2026-06-30
Inland Flooding84518301996 to 2026-06-30
Landslide0000001996 to 2026-06-30No recorded events, 1996 to 2026-06-30, NOAA NCEI Storm Events
Lightning7000001996 to 2026-06-30
Strong Wind48225983101955 to 2026-06-30Includes 10 High Wind and 15 Strong Wind records.
Tornado28001101950 to 2026-06-30
Tsunami0000001996 to 2026-06-30No recorded events, 1996 to 2026-06-30, NOAA NCEI Storm Events
Wildfire0000001996 to 2026-06-30No recorded events, 1996 to 2026-06-30, NOAA NCEI Storm Events
Winter Weather11782131011996 to 2026-06-30

Notable Storm Events records

Sources: 1, 6, 7

DateEvent typeMagnitude or extentDamagenominal dollarsDeaths, injuriesdirect onlyLocationFlagsWhy listed
2026-02-07High Wind56 kt (64 mph) measured gust$0 property; $0 crops (zone total, 2026 dollars)0, 0NWS zone MDZ016 (CHARLES), zone-levelnew since last plan; within last 5 yearsB1-c worst recorded: High Wind and Strong Wind
2026-01-23Extreme Cold/Wind Chill$0 property; $0 crops (zone total, 2026 dollars)0, 0NWS zone MDZ016 (CHARLES), zone-levelnew since last plan; within last 5 yearsB1-c worst recorded: Cold/Wind Chill, Extreme Cold/Wind Chill
2003-09-18Tropical Storm$5,700,000 property; $10,000 crops (zone total, 2003 dollars)0, 41NWS zone MDZ016 (CHARLES), zone-leveldeaths or injuries recorded
2002-08-12Heatdamage not reported0, 0NWS zone MDZ016 (CHARLES), zone-levelB1-c worst recorded: Excessive Heat, Heat
2002-04-28Hail4.5 indamage not reported0, 0LA PLATAB1-c worst recorded: Hail
2002-04-28TornadoF4, 24 mi within this county, 650 yd wide$114,000,000 property; crops not reported (2002 dollars)1, 122RISONdeaths or injuries recorded
2000-07-10Lightning$50,000 property; crops not reported (2000 dollars)0, 0BRYANS ROADB1-c worst recorded: Lightning
2000-06-15Thunderstorm Windspeed not recorded$5,000 property; crops not reported (2000 dollars)1, 0LA PLATAdeaths or injuries recorded
1999-08-25Flash Flood$200,000 property; crops not reported (1999 dollars)0, 0COUNTYWIDEB1-c worst recorded: Flash Flood, Flood, Lakeshore Flood
1999-05-01Droughtdamage not reported0, 0NWS zone MDZ016 (CHARLES), zone-levelB1-c worst recorded: Drought
1996-09-06Storm Surge/Tide$1,600,000 property; $5,000 crops (1996 dollars)0, 0ALONG THE POTOMACB1-c worst recorded: Coastal Flood, Storm Surge/Tide
1994-06-21Thunderstorm Wind72 kt (83 mph), measurement type not recordeddamage not recorded (pre-1996 record)0, 0CountywideB1-c worst recorded: Thunderstorm Wind

The full list is in the Excel file, sheet "B1-d Storm Events history" (955 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).

FEMA's declaration data list no tribal or special-area declarations for this state.

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
Coastal Flooding3.66events per year at a location (modeled)about 3.7 per year at a given location in the countyHighly likelyFEMA annualized frequency (modeled)not shownmodeledsee B1-fDescriptor from NRI: the rate at a location is 1 or more a year, so the county rate is at least that.
Cold Wave1.05event-days per yearabout 1.05 days per yearLikelyStorm Events event-days in 7 of 30 years, 1996 to 2025 (23.3%)202005-11-12 to 2024-11-12 (19 years)countywide
Drought2.89event-days per yearabout 2.89 days per yearLikelyStorm Events event-days in 3 of 30 years, 1996 to 2025 (10%)1192000 to 2025 (25.25 years; D3 and D4 only)countywide
Earthquake0.00147annual probability at a locationchance a given location in the county has at least minor-damage shaking in a year: 0.147%not shownmodeledsee B1-fNo descriptor (Storm Events does not record earthquakes).
Hail3.24events per yearabout 3.24 per yearHighly likelyFEMA annualized frequency (modeled)134.2 (modeled)1986 to 2023 (38 years)countywide
Heat Wave6.21event-days per yearabout 6.21 days per yearLikelyStorm Events event-days in 20 of 30 years, 1996 to 2025 (66.7%)1062005-11-12 to 2024-11-12 (19 years)countywide
Hurricane0.0906events per yearabout 1 in 11 yearsPossibleFEMA annualized frequency (modeled)261851 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 Storm0.402event-days per yearabout 0.402 days per yearLikelyStorm Events event-days in 3 of 30 years, 1996 to 2025 (10%)221946-12-31 to 2014-02-12 (67 years)countywide
Inland Flooding1.68event-days per yearabout 1.68 days per yearLikelyStorm Events event-days in 21 of 30 years, 1996 to 2025 (70%)471996 to 2023 (28 years)see B1-f
Landslide0.172events per year (modeled)about 1 in 6 yearsLikelyFEMA annualized frequency (modeled)not shownmodeledsee B1-f
Lightning39.7days per year with a strikeabout 39.7 days per yearHighly likelyFEMA annualized frequency (modeled)not shown1995 to 2023 (29 years; CONUS)countywide
Strong Wind6.24events per yearabout 6.24 per yearHighly likelyFEMA annualized frequency (modeled)1861986 to 2023 (38 years)countywide
Tornado0.449events per yearabout 1 in 2 yearsLikelyFEMA annualized frequency (modeled)not shown1950 to 2023 (EF2+); 1986 to 2023 (EF0-1)see B1-f
Tsunamiannual 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 shownmodeledsee B1-fNo descriptor: no Storm Events record 1996 to 2025
Wildfire0.000178annual probability at a locationchance a given location in the county burns in a year: 0.0178%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 Weather7.95event-days per yearabout 7.95 days per yearHighly likelyStorm Events event-days in 27 of 30 years, 1996 to 2025 (90%)1512005-11-12 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 202557301.9
Hail2.00 in+1996 to 20257300.233
Thunderstorm Wind (counted as NRI Strong Wind)50-64 kt1996 to 20253413011.4
Thunderstorm Wind (counted as NRI Strong Wind)65 kt+1996 to 20259300.3
Thunderstorm Wind (counted as NRI Strong Wind)unmeasured or below 50 kt1996 to 202546301.53
TornadoEF0-11996 to 202519300.633
TornadoEF2-31996 to 20251300.0333
TornadoEF4-51996 to 20251300.0333
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
Coastal Flooding12 of 3473.880.996.8Relatively High 1, Relatively Moderate 2, Relatively Low 4, Very Low 5, No Rating 22
Cold Wave34 of 3417.121.928.7Relatively Low 32, Very Low 2
Drought26 of 3467.185.697.8Relatively High 1, Relatively Moderate 7, Relatively Low 14, Very Low 4, No Rating 8
Earthquake34 of 3414.643.676.6Relatively Low 22, Very Low 12
Hail34 of 3428.549.967.4Relatively Low 31, Very Low 3
Heat Wave34 of 3414.858.885.3Relatively High 1, Relatively Moderate 20, Relatively Low 12, Very Low 1
Hurricane34 of 3451.869.280.2Relatively Moderate 2, Relatively Low 32
Ice Storm34 of 346.124.146.5Relatively Low 9, Very Low 25
Inland Flooding34 of 340.714.244.5Relatively Low 17, Very Low 17
Landslide34 of 3423.269.592.2Relatively Low 10, Very Low 24
Lightning34 of 3426.568.092.9Relatively High 10, Relatively Moderate 21, Relatively Low 3
Strong Wind34 of 3437.075.490.9Relatively High 12, Relatively Moderate 20, Relatively Low 2
Tornado34 of 349.129.541.9Relatively Low 17, Very Low 17
Tsunami0 of 34Insufficient Data 34
Wildfire34 of 3420.748.470.6Relatively Low 1, Very Low 33
Winter Weather34 of 3432.665.186.1Relatively High 2, Relatively Moderate 29, Relatively Low 3

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, heat wave, 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 planNotes
Charles CountyCountyApproved, expires 2029-12-09FMA RL 2, SRL 6; any 36$6,993,136.120 total; 0 since its planIncludes $139,821.24 for declarations not counted as hazard incidents (DR-4491-MD).
Indian Head townTownApproved, expires 2029-12-09FMA RL 0, SRL 0; any 0$164,821.8517 total; 0 since its plan
La Plata townTownApproved, expires 2029-12-09FMA RL 0, SRL 0; any 0$350,957.6956 total; 0 since its plan
Port Tobacco Village townTownPlan 110057 approved 2024-12-10, pending adoption here; not yet eligibleno Public Assistance recorded0 total; no approved planNo NFIP community ID on this jurisdiction's plan row.

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 2024-12-10county-coded records, property plus crops, nominal dollarsZone-level damage since planproperty plus crops, reported for the zonePublic Assistance since plannominal dollars; see noteNote
Coastal Flooding$304,130,109n/a1,405$272,501n/a$1,4300.0896%
Cold Wave$31,155,926,022$18,116,744166,485$23,853$13,714$259,943under 0.0001%$0
Droughtn/a$11,470,536n/an/a$965,097n/a8.41% (agriculture)NRI has no building exposure for this hazard; agriculture shown
Earthquake$51,258,921,618n/a166,617$907,546n/a$244,5370.00177%
Hail$31,155,926,022$18,116,744166,485$322,195$3,074$1,1170.00103%
Heat Wave$31,155,926,022$18,116,744166,485$131$91$2,284,682under 0.0001%$0
Hurricane$31,153,462,107$18,116,744166,471$2,238,081$61,666$74,1960.00718%
Ice Storm$30,868,341,128n/a165,168$78,220n/a$4,1270.000253%
Inland Flooding$31,140,615,632$550,505901$10,838,034$9,133$50,017n/a (see note)$0NRI 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$532,621,620n/a2,736$4,632n/a$820.00087%
Lightning$31,155,926,022n/a166,485$29,967n/a$893,698under 0.0001%
Strong Wind$31,155,926,022$18,116,744166,485$725,610$49,711$1,134,4720.00233%$369,000$0
Tornado$31,155,926,022$18,116,744166,485$601,956$335$182,3760.00193%
Tsunamin/an/an/an/an/an/aNRI publishes no building exposure for this county
Wildfire$1,532,969,572$1,975,57513,709$8,070$3$3,3760.000526%
Winter Weather$31,155,926,022$18,116,744166,485$19,226$4$198,417under 0.0001%$0no Public Assistance recorded (1 declaration)

Totals since 2024-12-10 (Storm Events through 2026-06-30): 30 county-coded records, 26 with a damage value recorded (including $0), $369,000; 13 zone-level records, 9 with a damage value recorded (including $0), $0 reported for the zone; Public Assistance: none recorded on the 1 counted declaration.

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
Population166,485
Building value (total, not at risk)$31,155,926,022
Agriculture value (total, not at risk)$18,116,744
NRI risk rating (all hazards)Relatively Low
Expected annual loss, buildings and agriculture, all hazards$17,172,849
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)$5,332,469
Social vulnerability ratingVery Low
Community resilience ratingVery High
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)2Severe repetitive loss, FMA definition (44 CFR 77.2)6
Repetitive loss, NFIP insurance definition34Severe repetitive loss, NFIP insurance definition5

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

Repeat-flood properties: county total and NFIP communities

Sources: 1, 4

ScopeRL, FMApropertiesSRL, FMApropertiesRL, NFIPpropertiesSRL, NFIPpropertiesAny categorypropertiesMitigatedpropertiesCurrently insuredproperties
County total2634536113
of which: Charles County (unincorporated area)2634536113

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

Sources: 1, 4

JurisdictionNFIP community IDRL, FMApropertiesSRL, FMApropertiesRL, NFIPpropertiesSRL, NFIPpropertiesAny categorypropertiesMitigatedpropertiesCurrently insuredproperties
Charles County2400892634536113
Indian Head town2400910000000
La Plata town2400920000000

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

Sources: 1, 4

Occupancy groupRL, FMApropertiesSRL, FMApropertiesRL, NFIPpropertiesSRL, NFIPpropertiesAny categorypropertiesMitigatedpropertiesCurrently insuredproperties
single-family residential1528429111
2 to 4 unit residential0000000
other residential0000000
non-residential1161702
not reported0000000

FEMA's occupancy groups have no institutional class; institutional properties are counted in non-residential or other residential in the table by occupancy group.

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 1 property is FMA repetitive loss but not NFIP repetitive loss, and 33 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 (the summary on page 1 says how it is organized); the plan and FEMA's review decide whether each 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). Charles County, MD: risk-assessment baseline packet, release 2026-10 (data as of 2026-09-30; County FIPS 24017). Automated baseline. https://hazardplain.org/md/24017/ 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]