Hazard Plain Automated baseline

Arapahoe County, CO

Risk-assessment baseline packet

County FIPS:
08005
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: Expired on 2026-01-12. Plan: Arapahoe County, CO Hazard Mitigation Plan 2021 (FEMA plan 107012), approved 2021-01-13.

Update: FEMA tracker shows a plan in review.

Since the plan was approved on 2021-01-13: 1 new hazard declaration (1 incident) and 238 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): Hail ($63,981,567 a year), Inland Flooding ($62,030,206) and Tornado ($22,358,910).

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:
Expired on 2026-01-12
Plan:
Arapahoe County, CO Hazard Mitigation Plan 2021 (FEMA plan 107012)
Approved:
2021-01-13
Days since expiry:
261
Update underway:
FEMA tracker shows a plan in review

Until a new plan is approved, FEMA mitigation project grants (HMGP, FMA) need a FEMA exception (44 CFR 201.6(a)(3)).

What changed since your last plan (approved 2021-01-13)

New federal declarations:
1 new hazard declaration (1 incident): DR-4731-CO (Severe Storms, Flooding, and Tornadoes)
Storm Events records since approval:
238 records (data through 2026-06-30)
Repetitive loss now:
FMA RL 0, SRL 0 (44 CFR 77.2); any definition: 6
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: 14 rows, in the section "Plan clock: Plan status for every jurisdiction listed in this county" on the following pages.

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

Plan clock

Plan status for every jurisdiction listed in this county

Source: 1

JurisdictionTypeStatusPlanApprovedExpiresDays to expirynegative = days since expiryUpdate underwayNotes
Arapahoe CountyCountyExpired on 2026-01-12Arapahoe County, CO Hazard Mitigation Plan 2021 (FEMA plan 107012)2021-01-132026-01-12-261FEMA tracker shows a plan in review
Aurora cityCityApproved, expires 2027-02-10City of Aurora Hazard Mitigation Plan 2021 (FEMA plan 107830)2022-02-112027-02-10133
Bennett townTownExpired on 2026-01-12Arapahoe County, CO Hazard Mitigation Plan 2021 (FEMA plan 107012)2021-01-132026-01-12-261FEMA tracker shows a plan approvable pending adoptionNot yet eligible: adopt the approved plan.
Bow Mar townTownExpired on 2026-01-12Arapahoe County, CO Hazard Mitigation Plan 2021 (FEMA plan 107012)2021-01-132026-01-12-261
Centennial cityCityExpired on 2026-01-12Arapahoe County, CO Hazard Mitigation Plan 2021 (FEMA plan 107012)2021-01-132026-01-12-261FEMA tracker shows a plan in review
Cherry Hills Village cityTownExpired on 2026-01-12Arapahoe County, CO Hazard Mitigation Plan 2021 (FEMA plan 107012)2021-01-132026-01-12-261FEMA tracker shows a plan in review
Englewood cityCityExpired on 2026-01-12Arapahoe County, CO Hazard Mitigation Plan 2021 (FEMA plan 107012)2021-01-132026-01-12-261FEMA tracker shows a plan in review
Foxfield townTownExpired on 2026-01-12Arapahoe County, CO Hazard Mitigation Plan 2021 (FEMA plan 107012)2021-01-132026-01-12-261FEMA tracker shows a plan in review
Glendale cityCityExpired on 2026-01-12Arapahoe County, CO Hazard Mitigation Plan 2021 (FEMA plan 107012)2021-01-132026-01-12-261
Greenwood Village cityCityExpired on 2026-01-12Arapahoe County, CO Hazard Mitigation Plan 2021 (FEMA plan 107012)2021-01-132026-01-12-261FEMA tracker shows a plan in review
Littleton cityCityExpired on 2026-01-12Arapahoe County, CO Hazard Mitigation Plan 2021 (FEMA plan 107012)2021-01-132026-01-12-261FEMA tracker shows a plan in review
Sheridan cityCityExpired on 2026-01-12Arapahoe County, CO Hazard Mitigation Plan 2021 (FEMA plan 107012)2021-01-132026-01-12-261FEMA tracker shows a plan in review
Denver WaterWater/Sewer AuthorityExpired on 2026-01-12Arapahoe County, CO Hazard Mitigation Plan 2021 (FEMA plan 107012)2021-01-132026-01-12-261FEMA tracker shows a plan in review
South Metro Fire RescueFire/EMS DistrictNo approved plan on recordnonenonenoneFEMA tracker shows a plan in review

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 2026-06-30countWhy this hazard can be left outNRI Not Applicable, no declaration and no Storm Events record since 1996Storm Events coverage note
1HailVery HighVery High$61,945,315$120,989$1,915,262$63,981,567460
2Inland FloodingRelatively ModerateRelatively High$61,429,254$6,208$594,744$62,030,20645
3TornadoRelatively HighRelatively High$17,250,067$2,103$5,106,741$22,358,91049
4Cold WaveRelatively HighRelatively High$71,652$35,363$9,290,285$9,397,29911Includes 1 Frost/Freeze record (outside NRI's Cold Wave definition; counted in this table and in B1-d, not in the B1-e descriptor).
5LightningVery HighVery High$67,770n/a$3,959,032$4,026,80230
6Strong WindRelatively HighRelatively High$1,067,733$2,777$2,647,187$3,717,697221Includes 110 High Wind and 7 Strong Wind records (NOAA non-thunderstorm wind types, outside NRI's Strong Wind definition).
7EarthquakeRelatively LowRelatively Moderate$2,669,023n/a$852,384$3,521,407Storm Events does not record earthquakes.
8Heat WaveRelatively LowRelatively Low$216$667$1,024,274$1,025,1575
9WildfireRelatively LowRelatively Low$740,201$94$61,826$802,1202
10Winter WeatherRelatively HighRelatively High$133,277$5$385,504$518,786283
11DroughtRelatively LowRelatively Lown/a$117,648n/a$117,6485
12Ice StormVery LowVery Low$5,423n/a$1,882$7,3050No recorded events in Storm Events since 1996 (data through 2026-06-30).
13LandslideVery LowVery Low$1,638n/a$15$1,6520Declared 1 time; no Storm Events record of this type.
14Volcanic ActivityVery LowVery Lowunder $1n/a$155$1550No recorded events in Storm Events since 1996 (data through 2026-06-30).
AvalancheNot ApplicableNot Applicable1NRI rates this Not Applicable, but 1 Storm Events record of this type exists since 1996; review before omitting.
HurricaneNot ApplicableNot Applicable0NRI rates hurricane Not Applicable for this county, and no counted federal declaration for this county names it (EM-3224-CO names it but is not counted as a local occurrence; see B1-d).No 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 landslide and volcanic activity 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: coastal flooding and tsunami. 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
Avalancheno tract has a National Risk Index rating for this hazard
Earthquaketract 73.02 (Relatively Low, 72.2); tract 67.12 (Relatively Low, 72.1); tract 66.01 (Relatively Low, 71.8)
Hurricaneno tract has a National Risk Index rating for this hazard
Landslidetract 71.06 (Relatively Low, 87.6); tract 71.01 (Relatively Low, 85.5); tract 867 (Very Low, 80.2)
Tornadotract 67.12 (Very High, 96.3); tract 67.04 (Relatively High, 88.7); tract 68.64 (Relatively High, 86.3)
Volcanic Activitytract 821 (Very Low, 77.6); tract 834 (Very Low, 77.5); tract 831 (Very Low, 76.0)
Wildfiretract 71.01 (Relatively High, 96.4); tract 71.03 (Relatively Moderate, 95.3); tract 867 (Relatively Moderate, 92.8)

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 73.02 is Census Tract 73.02). 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)1 record, 2015 (1 zone-level)No damage reported in 1 record.Countywide (zone-level records).
Cold/Wind Chill, Extreme Cold/Wind Chillwind chill10 records, 1996 to 2025 (10 zone-level)1 day to 7 days (median 3 days); 8 with a recorded value7 consecutive days, 1998-12-18 to 1998-12-24, 3 direct deaths, zone-levelCountywide (zone-level records).
Frost/Freeze (outside NRI's Cold Wave definition)crop damage1 record, 2014 (1 zone-level)Frost/Freeze, 2014-11-10, $10,000,000 crop damage (2014 dollars); NWS zone COZ040Countywide (zone-level records).
DroughtU.S. Drought Monitor scale (D0 to D4)5 records, 2002 to 2021 (5 zone-level)22 days to 61 days (median 30.5 days); 4 with a recorded value61 days (2 months), 2021-11-01 to 2021-12-31, a run of 2 consecutive Storm Events drought records, zone-levelCountywide (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)601 records, 1962 to 20260.75 in to 4.25 in (median 1 in); 599 with a recorded value4.25 in hail, 2010-06-10Hail, 2018-06-19, $276,400,000 property; crops not reported (2018 dollars)Event records naming jurisdictions in the plan: Littleton city (23 records), Englewood city (11 records), Aurora city (6 records), Bow Mar town (6 records), Sheridan city (6 records), Bennett town (3 records).
Excessive Heat, Heatheat index (in event narratives)5 records, 2000 to 2012 (5 zone-level)2 days to 30 days (median 17 days); 3 with a recorded valueJune 2012 (1 monthly summary record), zone-levelCountywide (zone-level records).
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)0
Flash Flood, Flood, Lakeshore Flooddamage and flood days (flood depth: FIRM)45 records, 1997 to 2025 (1 zone-level)Flood, 2013-09-12, $3,300,000 property; $0 crops (2013 dollars)Event records naming jurisdictions in the plan: Littleton city (2 records), Englewood city (1 record). Zone-level records (1) 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)30 records, 1996 to 2019Lightning, 2000-08-16, $250,000 property; crops not reported (2000 dollars)Event records naming jurisdictions in the plan: Littleton city (5 records), Englewood city (2 records).Storm Events lists lightning with damage or casualties.
High Wind and Strong Wind (outside NRI's Strong Wind definition)wind speed (kt and mph)117 records, 1996 to 2026 (117 zone-level)30 kt (35 mph) to 89 kt (102 mph) (median 55 kt (63 mph)); 115 with a recorded value89 kt (102 mph), measurement type not recorded, High Wind, 1999-02-02; NWS zone COZ040High Wind, 1997-12-28, $120,000 property; $0 crops (zone total, 1997 dollars)Countywide (zone-level records).
Thunderstorm Windwind speed (kt and mph)150 records, 1964 to 202650 kt (58 mph) to 80 kt (92 mph) (median 54 kt (62 mph)); 137 with a recorded value80 kt (92 mph), measurement type not recorded, Thunderstorm Wind, 1999-08-28Thunderstorm Wind, 1993-09-18, $500,000 property; crops not recorded (1993 dollars)Event records naming jurisdictions in the plan: Englewood city (5 records), Aurora city (2 records), Littleton city (2 records), Sheridan city (1 record).
TornadoEnhanced Fujita (Fujita before Feb 2007)98 records, 1964 to 2025F/EF0 to F/EF2 (median F/EF0); 95 with a recorded valueF2 tornado, 1986-06-08, 0.1 mi path length (whole path, pre-1996), 50 yd wide, $2,500,000 property; crops not recorded (1986 dollars)Tornado, 2002-08-29, $6,000,000 property; crops not reported (2002 dollars)Event records naming jurisdictions in the plan: Bennett town (1 record), Englewood city (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).
Volcanic Ash, Volcanic AshfallVolcanic Explosivity Index (local data)0
Wildfireacres burned (local data)2 records, 2024 to 2026 (2 zone-level)Wildfire, 2024-07-13, $750,000 property; crops not reported (2024 dollars); NWS zone COZ045Countywide (zone-level records).
Winter Storm, Heavy Snow, Blizzard, Lake-Effect Snow, Winter Weather, Sleetnone in data (snowfall: local data)283 records, 1996 to 2026 (283 zone-level)Blizzard, 2003-03-17, $15,500,000 property; crops not reported (2003 dollars), 2 direct injuries (reported for the zone); NWS zone COZ040Countywide (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 avalanche, debris flow, lightning and volcanic ash, volcanic ashfall.

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.

A monthly summary record covers most or all of a month; it does not count days at wave conditions.

Supports FEMA checklist item B1-d: previous occurrences

Federal declarations for this county: 12 declarations covering 8 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
2023-08-252023-06-08DR-4731-COMajor disasterSevere Storms, Flooding, and TornadoesInland Flooding (primary); also designated: Tornado$4,058,465.65new since last plan; within last 5 years
2020-03-282020-01-20DR-4498-COMajor disasterCOVID-19 PandemicNon-natural, not counted$4,731,308.71in the 12 months before plan approval
2020-03-132020-01-20EM-3436-COEmergencyCOVID-19Non-natural, not countedno Public Assistance recordedin the 12 months before plan approvalsame incident as DR-4498
2013-09-142013-09-11DR-4145-COMajor disasterSevere Storms, Flooding, Landslides, and MudslidesInland Flooding (primary); also designated: Landslide$2,724,330.80
2013-09-122013-09-11EM-3365-COEmergencySevere Storms, Flooding, Landslides, and MudslidesInland Flooding (primary); also designated: Landslideno Public Assistance recordedsame incident as DR-4145
2007-01-072006-12-18EM-3270-COEmergencySnowWinter Weather$895,301.08
2005-09-052005-08-29EM-3224-COEmergencyHurricane Katrina EvacuationHurricane: evacuation support, not a local hazard event; not countedno Public Assistance recorded
2003-04-092003-03-17EM-3185-COEmergencySnowWinter Weather$615,595.44
2002-06-192002-04-23DR-1421-COMajor disasterWildfiresWildfirePA not declared for this county
1973-05-231973-05-23DR-385-COMajor disasterHeavy Rains, Snowmelt and FloodingInland Floodingno Public Assistance recorded
1969-05-191969-05-19DR-261-COMajor disasterSevere Storms & FloodingInland Floodingno Public Assistance recorded
1965-06-191965-06-19DR-200-COMajor disasterTornadoes, Severe Storms & FloodingTornado (primary); also designated: Inland Floodingno 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
1956-06-121956-06-12DR-59-COMajor disasterFloodInland Flooding
1955-05-251955-05-25DR-33-COMajor disasterFloodInland 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.

10 Fire Management declarations (1978-09-12 to 2016-07-10) FEMA filed as Statewide with no county; each names one local fire. Listed on the state page.

Public Assistance filed under this county for declarations that do not list it: 2 rows, $581,850.76

Sources: 2, 3

FEMA numberDeclaredTitleApplicantPA obligatedfederal share obligated, nominal dollars
DR-4229-CO2015-07-16Severe Storms, Tornadoes, Flooding, Landslides, and MudslidesAURORA$568,530.08
EM-3271-CO2007-01-07SnowCatholic Health Initiatives Colorado$13,320.68

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.

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
Avalanche1000001996 to 2026-06-30
Cold Wave11404001996 to 2026-06-30Includes 1 Frost/Freeze record.
Drought5202001996 to 2026-06-30
Earthquake000000Storm Events does not record earthquakes; the USGS earthquake catalog is the source.
Hail60198486001955 to 2026-06-30
Heat Wave5000001996 to 2026-06-30
Hurricane0000001996 to 2026-06-30No recorded events, 1996 to 2026-06-30, NOAA NCEI Storm Events
Ice Storm0000001996 to 2026-06-30No recorded events, 1996 to 2026-06-30, NOAA NCEI Storm Events
Inland Flooding45606511996 to 2026-06-30
Landslide0000101996 to 2026-06-30No Storm Events records of this type; 1 federal declared incident (see declarations table)
Lightning30000001996 to 2026-06-30
Strong Wind267492546001955 to 2026-06-30Includes 110 High Wind and 7 Strong Wind records.
Tornado98605211950 to 2026-06-30
Volcanic Activity0000001996 to 2026-06-30No recorded events, 1996 to 2026-06-30, NOAA NCEI Storm Events
Wildfire2202101996 to 2026-06-30
Winter Weather28371859201996 to 2026-06-30

Notable Storm Events records

Sources: 1, 6, 7

DateEvent typeMagnitude or extentDamagenominal dollarsDeaths, injuriesdirect onlyLocationFlagsWhy listed
2024-07-13Wildfire$750,000 property; crops not reported (zone total, 2024 dollars)0, 0NWS zone COZ045 (C & E ADAMS & ARAPAHOE COUNTIES), zone-levelnew since last plan; within last 5 yearsB1-c worst recorded: Wildfire
2023-06-21Flash Flood$50,000 property; $0 crops (2023 dollars)1, 0ARAPAHOE PARKnew since last plan; within last 5 yearsdeaths or injuries recorded
2022-12-21Cold/Wind Chilldamage not reported1, 0NWS zone COZ040 (N DOUGLAS COUNTY BELOW 6000 FEET / DENVER / W ADAMS & ARAPAHOE COUNTIES / E BROOMFIELD COUNTY), zone-levelnew since last plan; within last 5 yearsdeaths or injuries recorded
2014-11-10Frost/Freezeproperty not reported; $10,000,000 crops (zone total, 2014 dollars)0, 0NWS zone COZ040 (N DOUGLAS COUNTY BELOW 6000 FEET / DENVER / W ADAMS & ARAPAHOE COUNTIES / E BROOMFIELD COUNTY), zone-levelB1-c worst recorded: Frost/Freeze
2013-09-12Flood$3,300,000 property; $0 crops (2013 dollars)0, 0SKYLINE to NORTH CHERRY VLY CREB1-c worst recorded: Flash Flood, Flood, Lakeshore Flood
2012-06-01Heat$0 property; $0 crops (zone total, 2012 dollars)0, 0NWS zone COZ040 (N DOUGLAS COUNTY BELOW 6000 FEET / DENVER / W ADAMS & ARAPAHOE COUNTIES / E BROOMFIELD COUNTY), zone-levelB1-c worst recorded: Excessive Heat, Heat
2010-06-10Hail4.25 indamage not reported0, 0DEER TRAILB1-c worst recorded: Hail
2000-08-16Lightning$250,000 property; crops not reported (2000 dollars)0, 0AURORA CHERRY CREEKB1-c worst recorded: Lightning
1999-08-28Thunderstorm Wind80 kt (92 mph), measurement type not recorded$20,000 property; crops not reported (1999 dollars)0, 0DEER TRAILB1-c worst recorded: Thunderstorm Wind
1999-02-02High Wind89 kt (102 mph), measurement type not recordeddamage not reported0, 0NWS zone COZ040 (DENVER METROPOLITAN AREA), zone-levelB1-c worst recorded: High Wind and Strong Wind
1998-12-18Cold/Wind Chillproperty not reported; $0 crops (zone total, 1998 dollars)3, 15NWS zone COZ040 (DENVER METROPOLITAN AREA), zone-leveldeaths or injuries recorded
1986-06-08TornadoF2, 0.1 mi path length (whole path, pre-1996), 50 yd wide$2,500,000 property; crops not recorded (1986 dollars)0, 0location not recordedB1-c worst recorded: Tornado

The full list is in the Excel file, sheet "B1-d Storm Events history" (1,348 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
Avalancheevents per year1994 to 2023 (30 years)see B1-fNot Applicable in NRI for this county; no descriptor.
Cold Wave1.61event-days per yearabout 1.61 days per yearLikelyStorm Events event-days in 8 of 30 years, 1996 to 2025 (26.7%)30.52005-11-12 to 2024-11-12 (19 years)countywide
Drought28.8event-days per yearabout 28.8 days per yearLikelyStorm Events event-days in 3 of 30 years, 1996 to 2025 (10%)1,0082000 to 2025 (25.25 years; D3 and D4 only)countywide
Earthquake0.000657annual probability at a locationchance a given location in the county has at least minor-damage shaking in a year: 0.0657%not shownmodeledsee B1-fNo descriptor (Storm Events does not record earthquakes).
Hail8.62events per yearabout 8.62 per yearHighly likelyFEMA annualized frequency (modeled)327.4 (modeled)1986 to 2023 (38 years)countywide
Heat Wave0.73event-days per yearabout 0.73 days per yearPossibleStorm Events event-days in 2 of 30 years, 1996 to 2025 (6.67%)10.92005-11-12 to 2024-11-12 (19 years)countywide
Hurricaneevents per year1851 to 2024 (Atlantic)see B1-fNot Applicable in NRI for this county; no descriptor.
Ice Storm0.026event-days per yearabout 0.026 days per yearStorm Events event-days in 0 of 30 years, 1996 to 2025 (0%)21946-12-31 to 2014-02-12 (67 years)countywideNo Storm Events ice storm record, 1996 to 2025
Inland Flooding1.32event-days per yearabout 1.32 days per yearLikelyStorm Events event-days in 19 of 30 years, 1996 to 2025 (63.3%)371996 to 2023 (28 years)see B1-f
Landslide0.151events per year (modeled)about 1 in 7 yearsLikelyFEMA annualized frequency (modeled)not shownmodeledsee B1-f
Lightning51.5days per year with a strikeabout 51.5 days per yearHighly likelyFEMA annualized frequency (modeled)not shown1995 to 2023 (29 years; CONUS)countywide
Strong Wind1.44events per yearabout 1.44 per yearHighly likelyFEMA annualized frequency (modeled)551986 to 2023 (38 years)countywide
Tornado1.06events per yearabout 1.06 per yearHighly likelyFEMA annualized frequency (modeled)not shown1950 to 2023 (EF2+); 1986 to 2023 (EF0-1)see B1-f
Volcanic Activity0.0001annual probabilityabout 1 in 10,000 yearsUnlikelyFEMA annualized frequency (modeled)not shownmodeledsee B1-f
Wildfire0.00149annual probability at a locationchance a given location in the county burns in a year: 0.149%PossibleStorm Events records in 1 of 30 years, 1996 to 2025 (3.33%)not shownmodeledsee B1-f
Winter Weather12.7event-days per yearabout 12.7 days per yearHighly likelyStorm Events event-days in 30 of 30 years, 1996 to 2025 (100%)2412005-11-12 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 2025299309.97
Hail2.00 in+1996 to 202538301.27
Thunderstorm Wind (counted as NRI Strong Wind)50-64 kt1996 to 202587302.9
Thunderstorm Wind (counted as NRI Strong Wind)65 kt+1996 to 202511300.367
Thunderstorm Wind (counted as NRI Strong Wind)unmeasured or below 50 kt1996 to 20252300.0667
TornadoEF0-11996 to 202545301.5
TornadoEF2-31996 to 20251300.0333
TornadoEF4-51996 to 20250300
Tornadounrated (EFU)1996 to 20253300.1

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
Avalanche0 of 161Not Applicable 161
Cold Wave161 of 16117.450.078.6Relatively High 2, Relatively Moderate 92, Relatively Low 66, Very Low 1
Drought22 of 16166.969.895.6Relatively Moderate 1, Relatively Low 4, Very Low 17, No Rating 139
Earthquake161 of 1619.334.772.2Relatively Low 63, Very Low 98
Hail161 of 16176.698.299.9Very High 85, Relatively High 73, Relatively Moderate 3
Heat Wave161 of 1611.96.927.5Relatively Low 7, Very Low 154
Hurricane0 of 161Not Applicable 161
Ice Storm161 of 1610.10.92.3Very Low 161
Inland Flooding161 of 1610.619.084.8Relatively High 2, Relatively Moderate 20, Relatively Low 69, Very Low 70
Landslide157 of 16110.044.087.6Relatively Low 2, Very Low 155, No Rating 4
Lightning161 of 1613.870.996.0Very High 2, Relatively High 50, Relatively Moderate 95, Relatively Low 13, Very Low 1
Strong Wind161 of 1619.753.682.0Relatively Moderate 79, Relatively Low 81, Very Low 1
Tornado161 of 16122.261.496.3Very High 1, Relatively High 18, Relatively Moderate 116, Relatively Low 25, Very Low 1
Volcanic Activity161 of 16140.956.977.6Very Low 161
Wildfire145 of 16118.549.396.4Relatively High 1, Relatively Moderate 6, Relatively Low 25, Very Low 113, No Rating 16
Winter Weather161 of 16117.051.177.2Relatively Moderate 104, Relatively Low 56, Very Low 1

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
Arapahoe CountyCountyExpired on 2026-01-12FMA RL 0, SRL 0; any 0$1,910,011.070 total; 0 since its plan
Aurora cityCityApproved, expires 2027-02-10FMA RL 0, SRL 0; any 3$3,468,232.558 total; 0 since its planWhole community, including the part in Adams County; in-county portion (county table): FMA RL 0, FMA SRL 0, NFIP RL 2, NFIP SRL 0, any category 2.
Bennett townTownExpired on 2026-01-12FMA RL 0, SRL 0; any 0no Public Assistance recorded4 total; 0 since its plan
Bow Mar townTownExpired on 2026-01-12FMA RL 0, SRL 0; any 0$4,5756 total; 5 since its plan
Centennial cityCityExpired on 2026-01-12FMA RL 0, SRL 0; any 0$151,529.600 total; 0 since its plan
Cherry Hills Village cityTownExpired on 2026-01-12FMA RL 0, SRL 0; any 2$12,128.800 total; 0 since its plan
Englewood cityCityExpired on 2026-01-12FMA RL 0, SRL 0; any 0$880,937.9520 total; 0 since its plan
Foxfield townTownExpired on 2026-01-12FMA RL 0, SRL 0; any 0$5,717.330 total; 0 since its plan
Glendale cityCityExpired on 2026-01-12FMA RL 0, SRL 0; any 0$11,800.710 total; 0 since its plan
Greenwood Village cityCityExpired on 2026-01-12FMA RL 0, SRL 0; any 0$182,889.850 total; 0 since its plan
Littleton cityCityExpired on 2026-01-12FMA RL 0, SRL 0; any 1$1,534,651.7132 total; 4 since its plan
Sheridan cityCityExpired on 2026-01-12FMA RL 0, SRL 0; any 0$5,291.157 total; 0 since its plan

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

School districts and special districts get a plan clock row only.

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 2021-01-13county-coded records, property plus crops, nominal dollarsZone-level damage since planproperty plus crops, reported for the zonePublic Assistance since plannominal dollars; see noteNote
AvalancheNot Applicable in NRI for this county
Cold Wave$119,555,813,892$34,340,948654,201$71,652$35,363$9,290,285under 0.0001%$0
Droughtn/a$19,156,289n/an/a$117,648n/a0.614% (agriculture)NRI has no building exposure for this hazard; agriculture shown
Earthquake$200,860,237,979n/a655,070$2,669,023n/a$852,3840.00133%
Hail$119,555,813,892$34,340,948654,201$61,945,315$120,989$1,915,2620.0518%$0
Heat Wave$119,555,813,892$34,340,948654,201$216$667$1,024,274under 0.0001%
HurricaneNot Applicable in NRI for this county
Ice Storm$119,555,813,892n/a654,201$5,423n/a$1,882under 0.0001%
Inland Flooding$119,454,682,133$729,5684,058$61,429,254$6,208$594,744n/a (see note)$170,000$4,058,465.65NRI 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$1,143,470,376n/a5,207$1,638n/a$150.000143%
Lightning$119,555,813,892n/a654,201$67,770n/a$3,959,032under 0.0001%
Strong Wind$119,555,813,892$34,340,948654,201$1,067,733$2,777$2,647,1870.000893%$6,000$0
Tornado$119,555,813,892$34,340,948654,201$17,250,067$2,103$5,106,7410.0144%$0$4,058,465.65
Volcanic Activity$119,555,813,892n/a654,201under $1n/a$155under 0.0001%
Wildfire$9,793,185,395$21,104,96359,487$740,201$94$61,8260.00756%$750,000
Winter Weather$119,555,813,892$34,340,948654,201$133,277$5$385,5040.000111%$0

Totals since 2021-01-13 (Storm Events through 2026-06-30): 139 county-coded records, 24 with a damage value recorded (including $0), $176,000; 99 zone-level records, 48 with a damage value recorded (including $0), $750,000 reported for the zone; Public Assistance: $4,058,465.65 on 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
Population654,201
Building value (total, not at risk)$119,555,813,892
Agriculture value (total, not at risk)$34,340,948
NRI risk rating (all hazards)Relatively Moderate
Expected annual loss, buildings and agriculture, all hazards$145,667,423
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)$25,839,289
Social vulnerability ratingVery Low
Community resilience ratingRelatively Moderate
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 definition6Severe 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 total0060604
of which: Aurora city0020201
of which: Cherry Hills Village city0020202
of which: Littleton city0010101
of which: Unknown (community ID Unknown in FEMA data)0010100
Statewide, no county in FEMA's file0080800

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 insuredpropertiesNote
Arapahoe County0800110000000
Aurora city0800020030301Whole community, including the part in Adams County; in-county portion (county table): FMA RL 0, FMA SRL 0, NFIP RL 2, NFIP SRL 0, any category 2.
Bennett town0800030000000
Bow Mar town0802320000000
Centennial city0803150000000
Cherry Hills Village city0800130020202
Englewood city0850740000000
Foxfield town0800910000000
Glendale city0802470000000
Greenwood Village city0801950000000
Littleton city0800170010101
Sheridan city0800180000000

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 residential0050503
2 to 4 unit residential0000000
other residential0010101
non-residential0000000
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 0 properties are FMA repetitive loss but not NFIP repetitive loss, and 6 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). Arapahoe County, CO: risk-assessment baseline packet, release 2026-10 (data as of 2026-09-30; County FIPS 08005). Automated baseline. https://hazardplain.org/co/08005/ 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]