Hazard Plain Automated baseline

Ada County, ID

Risk-assessment baseline packet

County FIPS:
16001
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 2027-11-08. Plan: Ada County Hazard Mitigation Plan (FEMA plan 107862), approved 2022-11-09.

Update: FEMA tracker shows a plan in progress.

Since the plan was approved on 2022-11-09: no new hazard declaration and 57 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 ($62,979,260 a year), Wildfire ($26,590,644) and Heat Wave ($7,006,169).

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 2027-11-08
Plan:
Ada County Hazard Mitigation Plan (FEMA plan 107862)
Approved:
2022-11-09
Days to expiry:
404
Update underway:
FEMA tracker shows a plan in progress

What changed since your last plan (approved 2022-11-09)

New federal declarations:
none
Storm Events records since approval:
57 records (data through 2026-06-30)
Repetitive loss now:
FMA RL 0, SRL 0 (44 CFR 77.2); any definition: 2
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: 23 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
Ada CountyCountyApproved, expires 2027-11-08Ada County Hazard Mitigation Plan (FEMA plan 107862)2022-11-092027-11-08404FEMA tracker shows a plan in progressthis jurisdiction approved 2022-11-28
Boise City cityCityApproved, expires 2027-11-08Ada County Hazard Mitigation Plan (FEMA plan 107862)2022-11-092027-11-08404FEMA tracker shows a plan in progressthis jurisdiction approved 2023-01-25
Eagle cityCityApproved, expires 2027-11-08Ada County Hazard Mitigation Plan (FEMA plan 107862)2022-11-092027-11-08404FEMA tracker shows a plan in progressthis jurisdiction approved 2023-01-25
Garden City cityCityApproved, expires 2027-11-08Ada County Hazard Mitigation Plan (FEMA plan 107862)2022-11-092027-11-08404FEMA tracker shows a plan in progressthis jurisdiction approved 2022-11-28
Kuna cityCityApproved, expires 2027-11-08Ada County Hazard Mitigation Plan (FEMA plan 107862)2022-11-092027-11-08404FEMA tracker shows a plan in progressthis jurisdiction approved 2023-04-06
Meridian cityCityApproved, expires 2027-11-08Ada County Hazard Mitigation Plan (FEMA plan 107862)2022-11-092027-11-08404FEMA tracker shows a plan in progressthis jurisdiction approved 2023-01-25
Star cityCityApproved, expires 2027-11-08Ada County Hazard Mitigation Plan (FEMA plan 107862)2022-11-092027-11-08404FEMA tracker shows a plan in progressthis jurisdiction approved 2022-11-28
Boise City Independent School District 1School/School DistrictApproved, expires 2027-11-08Ada County Hazard Mitigation Plan (FEMA plan 107862)2022-11-092027-11-08404FEMA tracker shows a plan in progressthis jurisdiction approved 2023-01-25
Meridian Joint School District 2School/School DistrictApproved, expires 2027-11-08Ada County Hazard Mitigation Plan (FEMA plan 107862)2022-11-092027-11-08404FEMA tracker shows a plan in progressthis jurisdiction approved 2024-01-03
Ada County Highway DistrictHighway/Port/RailApproved, expires 2027-11-08Ada County Hazard Mitigation Plan (FEMA plan 107862)2022-11-092027-11-08404FEMA tracker shows a plan in progressthis jurisdiction approved 2023-01-25
Boise River Flood Control DistrictFlood Control DistrictApproved, expires 2027-11-08Ada County Hazard Mitigation Plan (FEMA plan 107862)2022-11-092027-11-08404FEMA tracker shows a plan in progressthis jurisdiction approved 2023-01-25
Boise State UniversityCollege/UniversityExpired on 2026-03-09Boise State University Hazard Mitigation Plan (FEMA plan 107708)2021-03-102026-03-09-205
Eagle Fire Protection DistrictFire/EMS DistrictApproved, expires 2027-11-08Ada County Hazard Mitigation Plan (FEMA plan 107862)2022-11-092027-11-08404FEMA tracker shows a plan in progressthis jurisdiction approved 2023-01-25
Eagle Sewer DistrictWater/Sewer AuthorityApproved, expires 2027-11-08Ada County Hazard Mitigation Plan (FEMA plan 107862)2022-11-092027-11-08404FEMA tracker shows a plan in progressthis jurisdiction approved 2023-04-06
Eagle Urban Renewal AgencyOtherApproved, expires 2027-11-08Ada County Hazard Mitigation Plan (FEMA plan 107862)2022-11-092027-11-08404FEMA tracker shows a plan in progressthis jurisdiction approved 2024-01-03
Greater Boise Auditorium DistrictSpecial DistrictApproved, expires 2027-11-08Ada County Hazard Mitigation Plan (FEMA plan 107862)2022-11-092027-11-08404FEMA tracker shows a plan in progressthis jurisdiction approved 2023-01-25
Kuna Rural Fire DistrictFire/EMS DistrictApproved, expires 2027-11-08Ada County Hazard Mitigation Plan (FEMA plan 107862)2022-11-092027-11-08404FEMA tracker shows a plan in progressthis jurisdiction approved 2024-01-03
Meredian Development CorporationOtherApproved, expires 2027-11-08Ada County Hazard Mitigation Plan (FEMA plan 107862)2022-11-092027-11-08404FEMA tracker shows a plan in progressthis jurisdiction approved 2024-01-03
North Ada County Fire and Rescue DistrictFire/EMS DistrictApproved, expires 2027-11-08Ada County Hazard Mitigation Plan (FEMA plan 107862)2022-11-092027-11-08404FEMA tracker shows a plan in progressthis jurisdiction approved 2022-11-28
Star Fire DistrictFire/EMS DistrictApproved, expires 2027-11-08Ada County Hazard Mitigation Plan (FEMA plan 107862)2022-11-092027-11-08404FEMA tracker shows a plan in progressthis jurisdiction approved 2024-01-03
Star Sewer and Water DistrictWater/Sewer AuthorityApproved, expires 2027-11-08Ada County Hazard Mitigation Plan (FEMA plan 107862)2022-11-092027-11-08404FEMA tracker shows a plan in progressthis jurisdiction approved 2022-11-28
West Ada School DistrictSchool/School DistrictApproved, expires 2027-11-08Ada County Hazard Mitigation Plan (FEMA plan 107862)2022-11-092027-11-08404FEMA tracker shows a plan in progressthis jurisdiction approved 2024-01-03
Whitney Fire Protection DistrictFire/EMS DistrictApproved, expires 2027-11-08Ada County Hazard Mitigation Plan (FEMA plan 107862)2022-11-092027-11-08404FEMA tracker shows a plan in progressthis jurisdiction approved 2024-04-06

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
1Inland FloodingRelatively ModerateRelatively High$62,869,682$9,757$99,822$62,979,26024
2WildfireRelatively HighRelatively High$25,131,411$1,917$1,457,316$26,590,6446
3Heat WaveRelatively ModerateRelatively Moderate$1,563$21,238$6,983,368$7,006,1690No recorded events in Storm Events since 1996 (data through 2026-06-30).
4EarthquakeRelatively LowRelatively Moderate$5,082,094n/a$1,544,330$6,626,424Storm Events does not record earthquakes.
5Strong WindRelatively HighRelatively High$84,342$882$3,718,583$3,803,807108Includes 24 High Wind and 4 Strong Wind records (NOAA non-thunderstorm wind types, outside NRI's Strong Wind definition).
6Winter WeatherVery HighVery High$6,821$1,133$2,993,594$3,001,54839
7LightningRelatively HighRelatively High$61,901n/a$1,936,775$1,998,6773
8Cold WaveRelatively LowRelatively Moderate$4,247$10,671$1,670,829$1,685,7471
9Ice StormRelatively ModerateRelatively High$27,671n/a$677,916$705,5870No recorded events in Storm Events since 1996 (data through 2026-06-30).
10TornadoRelatively LowRelatively Low$362,899$89$323,030$686,0188
11HailRelatively LowRelatively Low$426,481$11,094$87,191$524,76622
12LandslideRelatively LowVery Low$8,713n/a$187$8,9003
13DroughtVery LowVery Lown/a$783n/a$7830No recorded events in Storm Events since 1996 (data through 2026-06-30).
14Volcanic ActivityVery LowVery Low$1n/a$235$2350No recorded events in Storm Events since 1996 (data through 2026-06-30).
15AvalancheVery LowVery Low$3n/a$129$1320No recorded events in Storm Events since 1996 (data through 2026-06-30).
HurricaneNot ApplicableNot Applicable0NRI rates hurricane Not Applicable for this county, and no counted federal declaration for this county names it (EM-3244-ID 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 volcanic activity 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 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
Avalanchetract 105.03 (Very Low, 17.8); tract 101.01 (Very Low, 16.1); tract 105.01 (Very Low, 16.0)
Earthquaketract 1.02 (Relatively Moderate, 84.7); tract 20 (Relatively Moderate, 83.0); tract 9.02 (Relatively Moderate, 81.4)
Hurricaneno tract has a National Risk Index rating for this hazard
Landslidetract 2.02 (Relatively Low, 94.5); tract 101.01 (Relatively Low, 94.3); tract 101.02 (Relatively Low, 93.6)
Tornadotract 20 (Very Low, 28.3); tract 21 (Very Low, 23.8); tract 9.02 (Very Low, 23.4)
Volcanic Activitytract 20 (Very Low, 79.1); tract 103.67 (Very Low, 78.0); tract 105.01 (Very Low, 77.9)
Wildfiretract 105.03 (Very High, 99.9); tract 101.02 (Very High, 99.8); tract 101.01 (Very High, 99.6)

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 105.03 is Census Tract 105.03). 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)0
Cold/Wind Chill, Extreme Cold/Wind Chillwind chill1 record, 2002 (1 zone-level)2 days; 1 with a recorded value2 consecutive days, 2002-05-08 to 2002-05-09, zone-levelCountywide (zone-level records).
Frost/Freeze (outside NRI's Cold Wave definition)crop damage0
DroughtU.S. Drought Monitor scale (D0 to D4)0Storm 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)41 records, 1967 to 20240.75 in to 1.5 in (median 1 in); 41 with a recorded value1.5 in hail, 2015-05-26; same size also recorded on 1995-06-16, 1995-07-09, 2009-08-06, 2013-09-05Hail, 1995-07-09, $5,000 property; crops not recorded (1995 dollars)Event records naming jurisdictions in the plan: Eagle city (3 records), Meridian city (3 records), Star city (2 records), Kuna city (1 record).
Excessive Heat, Heatheat index (in event narratives)0
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)24 records, 1997 to 2025 (1 zone-level)Flash Flood, 2023-06-06, $1,000,000 property; $1,000,000 crops (2023 dollars)Event records naming jurisdictions in the plan: Star city (4 records), Eagle city (1 record), Garden City city (1 record), Meridian 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)3 records, 2025No damage reported in 3 records.No event record names a jurisdiction in the plan.
Lightningannualized frequency (the measure FEMA's Local Mitigation Planning Handbook names)3 records, 1997 to 1999Lightning, 1998-09-07, $10,000 property; crops not reported (1998 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)28 records, 1997 to 2026 (28 zone-level)34 kt (39 mph) to 74 kt (85 mph) (median 52 kt (60 mph)); 28 with a recorded value74 kt (85 mph) measured, High Wind, 2000-02-14; NWS zone IDZ014High Wind, 2009-03-29, $100,000 property; $0 crops (zone total, 2009 dollars)Countywide (zone-level records).
Thunderstorm Windwind speed (kt and mph)117 records, 1958 to 202650 kt (58 mph) to 80 kt (92 mph) (median 52 kt (60 mph)); 93 with a recorded value80 kt (92 mph), measurement type not recorded, Thunderstorm Wind, 1996-08-27Thunderstorm Wind, 1995-04-27, $500,000 property; crops not recorded (1995 dollars)Event records naming jurisdictions in the plan: Meridian city (10 records), Kuna city (8 records), Eagle city (2 records), Boise City city (1 record), Garden City city (1 record), Star city (1 record).
TornadoEnhanced Fujita (Fujita before Feb 2007)13 records, 1956 to 2023F/EF0 to F/EF1 (median F/EF0); 12 with a recorded valueF1 tornado, 1984-10-26, 0.3 mi path length (whole path, pre-1996), 50 yd wide, $25,000 property; crops not recorded (1984 dollars); same rating, casualties and property damage also recorded on 1984-03-21Event records naming jurisdictions in the plan: Eagle city (1 record), Kuna city (1 record), Star 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)6 records, 1997 to 2015 (5 zone-level)Wildfire, 2008-08-25, $5,000,000 property; $0 crops (2008 dollars), 1 direct death (reported for the zone); NWS zone IDZ014Event records naming jurisdictions in the plan: Eagle city (1 record). Zone-level records (5) apply countywide.
Winter Storm, Heavy Snow, Blizzard, Lake-Effect Snow, Winter Weather, Sleetnone in data (snowfall: local data)39 records, 1996 to 2025 (39 zone-level)No damage reported in 39 records.Countywide (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.

Supports FEMA checklist item B1-d: previous occurrences

Federal declarations for this county: 6 declarations covering 3 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 dollarsNotes
2020-04-092020-01-20DR-4534-IDMajor disasterCOVID-19 PandemicNon-natural, not counted$31,568,322.37
2020-03-132020-01-20EM-3467-IDEmergencyCOVID-19Non-natural, not countedno Public Assistance recordedsame incident as DR-4534
2017-10-072017-03-29DR-4342-IDMajor disasterFloodingInland Flooding$3,719,555.08
2005-09-132005-08-29EM-3244-IDEmergencyHurricane KatrinaHurricane: evacuation support, not a local hazard event; not countedno Public Assistance recorded
2000-09-012000-07-27DR-1341-IDMajor disasterWildfiresWildfirePA not declared for this county
1964-12-311964-12-31DR-186-IDMajor disasterHeavy Rains & FloodingInland Floodingno Public Assistance recorded

School districts and special districts in this county: $81,975.19 (included in the county total above). Public Assistance matched by applicant name to the school districts and special districts FEMA lists as plan participants in this county. They have no row of their own in the jurisdiction table, so their total is listed here. These dollars are already included in the county PA column of the declarations table (the FEMA record places each applicant in this county), so this line is not added to it.

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
1963-02-141963-02-14DR-143-IDMajor disasterFloodsInland Flooding
1962-02-141962-02-14DR-120-IDMajor disasterFloodsInland Flooding
1961-06-261961-06-26DR-116-IDMajor disasterFloodsInland Flooding
1960-07-221960-07-22DR-105-IDMajor disasterFiresWildfire
1957-05-271957-05-27DR-76-IDMajor disasterFloodInland Flooding
1956-04-211956-04-21DR-55-IDMajor 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.

2 Fire Management declarations (1977-08-20 to 1979-08-08) FEMA filed as Statewide with no county; each names one local fire. Listed on the state page.

Public Assistance not placed in any Idaho county: 1 row, $107,969.35; listed on the Idaho 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
Avalanche0000001996 to 2026-06-30No recorded events, 1996 to 2026-06-30, NOAA NCEI Storm Events
Cold Wave1000001996 to 2026-06-30
Drought0000001996 to 2026-06-30No recorded events, 1996 to 2026-06-30, NOAA NCEI Storm Events
Earthquake000000Storm Events does not record earthquakes; the USGS earthquake catalog is the source.
Hail41325001955 to 2026-06-30
Heat Wave0000001996 to 2026-06-30No recorded events, 1996 to 2026-06-30, NOAA NCEI Storm Events
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 Flooding24314201996 to 2026-06-30
Landslide3303001996 to 2026-06-30
Lightning3000001996 to 2026-06-30
Strong Wind14536137001955 to 2026-06-30Includes 24 High Wind and 4 Strong Wind records.
Tornado13101001950 to 2026-06-30
Volcanic Activity0000001996 to 2026-06-30No recorded events, 1996 to 2026-06-30, NOAA NCEI Storm Events
Wildfire6000101996 to 2026-06-30
Winter Weather3911415001996 to 2026-06-30

Notable Storm Events records

Sources: 1, 6, 7

DateEvent typeMagnitude or extentDamagenominal dollarsDeaths, injuriesdirect onlyLocationFlagsWhy listed
2023-06-06Flash Flood$1,000,000 property; $1,000,000 crops (2023 dollars)0, 0BOISEnew since last plan; within last 5 yearsB1-c worst recorded: Flash Flood, Flood, Lakeshore Flood
2015-05-26Hail1.5 indamage not reported0, 0STAR to BOISEB1-c worst recorded: Hail
2010-08-21Thunderstorm Wind59 kt (68 mph) measured gust$0 property; $0 crops (2010 dollars)0, 70(BOI)GOWEN FLD BOISEdeaths or injuries recorded
2009-03-29High Wind50 kt (58 mph) estimated gust$100,000 property; $0 crops (zone total, 2009 dollars)0, 0NWS zone IDZ014 (UPPER TREASURE VALLEY), zone-levelB1-c most damaging: High Wind and Strong Wind
2008-08-25Wildfire$5,000,000 property; $0 crops (zone total, 2008 dollars)1, 0NWS zone IDZ014 (UPPER TREASURE VALLEY), zone-leveldeaths or injuries recorded
2002-07-25Thunderstorm Wind54 kt (62 mph) measureddamage not reported0, 4MERIDIANdeaths or injuries recorded
2002-05-08Extreme Cold/Wind Chilldamage not reported0, 0NWS zone IDZ014 (UPPER TREASURE VALLEY), zone-levelB1-c worst recorded: Cold/Wind Chill, Extreme Cold/Wind Chill
2000-02-14High Wind74 kt (85 mph) measureddamage not reported0, 0NWS zone IDZ014 (UPPER TREASURE VALLEY), zone-levelB1-c worst recorded: High Wind and Strong Wind
1998-09-07Lightning$10,000 property; crops not reported (1998 dollars)0, 0BOISEB1-c worst recorded: Lightning
1996-08-27Thunderstorm Wind80 kt (92 mph), measurement type not recordeddamage not reported0, 0ORCHARDB1-c worst recorded: Thunderstorm Wind
1995-04-27Thunderstorm Windspeed not recorded$500,000 property; crops not recorded (1995 dollars)0, 0StarB1-c most damaging: Thunderstorm Wind
1984-10-26TornadoF1, 0.3 mi path length (whole path, pre-1996), 50 yd wide$25,000 property; crops not recorded (1984 dollars)0, 0location not recordedB1-c worst recorded: Tornado

The full list is in the Excel file, sheet "B1-d Storm Events history" (275 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 Wave0.105event-days per yearabout 0.105 days per yearPossibleStorm Events event-days in 1 of 30 years, 1996 to 2025 (3.33%)22005-11-12 to 2024-11-12 (19 years)countywide
Drought14.3event-days per yearabout 14.3 days per yearStorm Events event-days in 0 of 30 years, 1996 to 2025 (0%)4482000 to 2025 (25.25 years; D3 and D4 only)countywideNo Storm Events drought record, 1996 to 2025
Earthquake0.00248annual probability at a locationchance a given location in the county has at least minor-damage shaking in a year: 0.248%not shownmodeledsee B1-fNo descriptor (Storm Events does not record earthquakes).
Hail0.243events per yearabout 1 in 4 yearsLikelyFEMA annualized frequency (modeled)9.2 (modeled)1986 to 2023 (38 years)countywide
Heat Wave4.37event-days per yearabout 4.37 days per yearStorm Events event-days in 0 of 30 years, 1996 to 2025 (0%)422005-11-12 to 2024-11-12 (19 years)countywideNo Storm Events heat wave record, 1996 to 2025
Hurricaneevents per year1851 to 2024 (Atlantic)see B1-fNot Applicable in NRI for this county; no descriptor.
Ice Storm0.104event-days per yearabout 0.104 days per yearStorm Events event-days in 0 of 30 years, 1996 to 2025 (0%)71946-12-31 to 2014-02-12 (67 years)countywideNo Storm Events ice storm record, 1996 to 2025
Inland Flooding0.786event-days per yearabout 0.786 days per yearLikelyStorm Events event-days in 15 of 30 years, 1996 to 2025 (50%)221996 to 2023 (28 years)see B1-f
Landslide0.148events per year (modeled)about 1 in 7 yearsLikelyFEMA annualized frequency (modeled)not shownmodeledsee B1-f
Lightning19.8days per year with a strikeabout 19.8 days per yearHighly likelyFEMA annualized frequency (modeled)not shown1995 to 2023 (29 years; CONUS)countywide
Strong Wind0.332events per yearabout 1 in 3 yearsLikelyFEMA annualized frequency (modeled)131986 to 2023 (38 years)countywide
Tornado0.0554events per yearabout 1 in 18 yearsPossibleFEMA annualized frequency (modeled)not shown1950 to 2023 (EF2+); 1986 to 2023 (EF0-1)see B1-f
Volcanic Activity0.0002annual probabilityabout 1 in 5,000 yearsUnlikelyFEMA annualized frequency (modeled)not shownmodeledsee B1-f
Wildfire0.0115annual probability at a locationchance a given location in the county burns in a year: 1.15%LikelyStorm Events records in 5 of 30 years, 1996 to 2025 (16.7%)not shownmodeledsee B1-f
Winter Weather8.86event-days per yearabout 8.86 days per yearLikelyStorm Events event-days in 19 of 30 years, 1996 to 2025 (63.3%)1682005-11-12 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.

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 202516300.533
Hail2.00 in+1996 to 20250300
Thunderstorm Wind (counted as NRI Strong Wind)50-64 kt1996 to 202569302.3
Thunderstorm Wind (counted as NRI Strong Wind)65 kt+1996 to 20252300.0667
Thunderstorm Wind (counted as NRI Strong Wind)unmeasured or below 50 kt1996 to 20251300.0333
TornadoEF0-11996 to 20258300.267
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
Avalanche3 of 12916.016.117.8Very Low 3, Not Applicable 126
Cold Wave129 of 12919.324.435.8Relatively Low 129
Drought72 of 12966.867.475.5Very Low 72, No Rating 57
Earthquake129 of 12916.745.584.7Relatively Moderate 6, Relatively Low 69, Very Low 54
Hail129 of 12920.634.761.2Relatively Low 49, Very Low 80
Heat Wave129 of 12919.553.781.5Relatively Moderate 55, Relatively Low 74
Hurricane0 of 129Not Applicable 129
Ice Storm129 of 12919.346.073.3Relatively Moderate 1, Relatively Low 111, Very Low 17
Inland Flooding129 of 1291.421.988.7Relatively High 5, Relatively Moderate 18, Relatively Low 61, Very Low 45
Landslide101 of 1298.612.494.5Relatively Low 7, Very Low 94, No Rating 28
Lightning129 of 12921.450.285.2Relatively High 1, Relatively Moderate 68, Relatively Low 60
Strong Wind129 of 12929.858.983.7Relatively High 1, Relatively Moderate 76, Relatively Low 52
Tornado129 of 1293.59.228.3Very Low 129
Volcanic Activity129 of 12945.270.479.1Very Low 129
Wildfire94 of 12918.987.699.9Very High 5, Relatively High 8, Relatively Moderate 28, Relatively Low 29, Very Low 24, No Rating 35
Winter Weather129 of 12970.291.698.2Very High 12, Relatively High 110, Relatively Moderate 7

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
Ada CountyCountyApproved, expires 2027-11-08FMA RL 0, SRL 0; any 0$313,414.710 total; 0 since its planIncludes $114,650.29 for declarations not counted as hazard incidents (DR-4534-ID).
Boise City cityCityApproved, expires 2027-11-08FMA RL 0, SRL 0; any 0no Public Assistance recorded1 total; 0 since its plan
Eagle cityCityApproved, expires 2027-11-08FMA RL 0, SRL 0; any 1$1,325,723.918 total; 2 since its plan
Garden City cityCityApproved, expires 2027-11-08FMA RL 0, SRL 0; any 1$36,274.502 total; 1 since its plan
Kuna cityCityApproved, expires 2027-11-08FMA RL 0, SRL 0; any 0no Public Assistance recorded10 total; 2 since its plan
Meridian cityCityApproved, expires 2027-11-08FMA RL 0, SRL 0; any 0$4,703.8514 total; 2 since its planIncludes $4,703.85 for declarations not counted as hazard incidents (DR-4534-ID).
Star cityCityApproved, expires 2027-11-08FMA RL 0, SRL 0; any 0no Public Assistance recorded8 total; 1 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 2022-11-09county-coded records, property plus crops, nominal dollarsZone-level damage since planproperty plus crops, reported for the zonePublic Assistance since plannominal dollars; see noteNote
Avalanche$68,385n/aunder 1$3n/a$1290.00398%
Cold Wave$93,099,516,499$169,457,276494,805$4,247$10,671$1,670,829under 0.0001%
Droughtn/a$50,724,232n/an/a$783n/a0.00154% (agriculture)NRI has no building exposure for this hazard; agriculture shown
Earthquake$160,213,301,555n/a494,967$5,082,094n/a$1,544,3300.00317%
Hail$93,099,516,499$169,457,276494,805$426,481$11,094$87,1910.000458%$0
Heat Wave$93,099,516,499$169,457,276494,805$1,563$21,238$6,983,368under 0.0001%
HurricaneNot Applicable in NRI for this county
Ice Storm$91,905,140,357n/a488,425$27,671n/a$677,916under 0.0001%
Inland Flooding$93,065,444,696$24,271,75214,185$62,869,682$9,757$99,822n/a (see note)$2,000,000NRI 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$1,208,938,067n/a4,670$8,713n/a$1870.000721%$0
Lightning$93,099,516,499n/a494,805$61,901n/a$1,936,775under 0.0001%
Strong Wind$93,099,516,499$169,457,276494,805$84,342$882$3,718,583under 0.0001%$0$0
Tornado$93,099,516,499$169,457,276494,805$362,899$89$323,0300.00039%
Volcanic Activity$93,099,516,499n/a494,805$1n/a$235under 0.0001%
Wildfire$6,341,241,382$73,339,05862,327$25,131,411$1,917$1,457,3160.396%
Winter Weather$93,099,516,499$169,457,276494,805$6,821$1,133$2,993,594under 0.0001%$0

Totals since 2022-11-09 (Storm Events through 2026-06-30): 41 county-coded records, 28 with a damage value recorded (including $0), $2,000,000; 16 zone-level records, 11 with a damage value recorded (including $0), $0 reported for the zone; Public Assistance: no counted declaration since the plan.

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
Population494,805
Building value (total, not at risk)$93,099,516,499
Agriculture value (total, not at risk)$169,457,276
NRI risk rating (all hazards)Relatively Moderate
Expected annual loss, buildings and agriculture, all hazards$94,125,394
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)$21,493,303
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)0Severe repetitive loss, FMA definition (44 CFR 77.2)0
Repetitive loss, NFIP insurance definition2Severe 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 total and NFIP communities

Sources: 1, 4

ScopeRL, FMApropertiesSRL, FMApropertiesRL, NFIPpropertiesSRL, NFIPpropertiesAny categorypropertiesMitigatedpropertiesCurrently insuredproperties
County total0020200
of which: Eagle city0010100
of which: Garden City city0010100

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

Sources: 1, 4

JurisdictionNFIP community IDRL, FMApropertiesSRL, FMApropertiesRL, NFIPpropertiesSRL, NFIPpropertiesAny categorypropertiesMitigatedpropertiesCurrently insuredproperties
Ada County1600010000000
Boise City city1600020000000
Eagle city1600030010100
Garden City city1600040010100
Kuna city1601740000000
Meridian city1601800000000
Star city1602360000000

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 residential0020200
2 to 4 unit residential0000000
other residential0000000
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 2 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). Ada County, ID: risk-assessment baseline packet, release 2026-10 (data as of 2026-09-30; County FIPS 16001). Automated baseline. https://hazardplain.org/id/16001/ 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: contact@hazardplain.org