Hazard Plain Automated baseline

Williams County, ND

Risk-assessment baseline packet

County FIPS:
38105
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 2022-11-02. Plan: Williams County, ND Hazard Mitigation Plan 2017 (FEMA plan 104661), approved 2017-11-02.

Update: FEMA tracker shows a plan approvable pending adoption.

Since the plan was approved on 2017-11-02: 4 new hazard declarations (4 incidents): DR-4613-ND (Severe Storm, Straight-Line Winds, and Flooding), DR-4660-ND (Severe Winter Storm and Flooding), DR-4852-ND (Wildfires and Straight-Line Winds), DR-4934-ND (Severe Storms, Straight-Line Winds, and Tornadoes); also 2 COVID-19 declarations (not counted).

NOAA Storm Events records since that date: 201 records (data through 2026-06-30).

Highest expected annual loss (FEMA National Risk Index, modeled total; see B1-a): Cold Wave ($10,659,062 a year), Inland Flooding ($7,551,831) and Tornado ($1,932,090).

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

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

Plan clock

Status:
Expired on 2022-11-02
Plan:
Williams County, ND Hazard Mitigation Plan 2017 (FEMA plan 104661)
Approved:
2017-11-02
Days since expiry:
1,428
Update underway:
FEMA tracker shows a plan approvable pending adoption

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

Not yet eligible: adopt the approved plan.

What changed since your last plan (approved 2017-11-02)

New federal declarations:
4 new hazard declarations (4 incidents): DR-4613-ND (Severe Storm, Straight-Line Winds, and Flooding), DR-4660-ND (Severe Winter Storm and Flooding), DR-4852-ND (Wildfires and Straight-Line Winds), DR-4934-ND (Severe Storms, Straight-Line Winds, and Tornadoes); also 2 COVID-19 declarations (not counted)
Storm Events records since approval:
201 records (data through 2026-06-30)
Repetitive loss now:
FMA RL 0, SRL 0 (44 CFR 77.2); any definition: 0
Repeat-flood change:
this release sets the baseline count.

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

Plan status for every jurisdiction listed in this county

Source: 1

JurisdictionTypeStatusPlanApprovedExpiresDays to expirynegative = days since expiryUpdate underwayNotes
Williams CountyCountyExpired on 2022-11-02Williams County, ND Hazard Mitigation Plan 2017 (FEMA plan 104661)2017-11-022022-11-02-1,428FEMA tracker shows a plan approvable pending adoptionNot yet eligible: adopt the approved plan.
Alamo cityCityExpired on 2022-11-02Williams County, ND Hazard Mitigation Plan 2017 (FEMA plan 104661)2017-11-022022-11-02-1,428FEMA tracker shows a plan approvable pending adoptionNot yet eligible: adopt the approved plan.
Epping cityCityExpired on 2022-11-02Williams County, ND Hazard Mitigation Plan 2017 (FEMA plan 104661)2017-11-022022-11-02-1,428FEMA tracker shows a plan approvable pending adoptionNot yet eligible: adopt the approved plan.
Grenora cityCityExpired on 2022-11-02Williams County, ND Hazard Mitigation Plan 2017 (FEMA plan 104661)2017-11-022022-11-02-1,428FEMA tracker shows a plan approvable pending adoptionNot yet eligible: adopt the approved plan.
Ray cityCityExpired on 2022-11-02Williams County, ND Hazard Mitigation Plan 2017 (FEMA plan 104661)2017-11-022022-11-02-1,428FEMA tracker shows a plan approvable pending adoptionNot yet eligible: adopt the approved plan.
Tioga cityCityExpired on 2022-11-02Williams County, ND Hazard Mitigation Plan 2017 (FEMA plan 104661)2017-11-022022-11-02-1,428FEMA tracker shows a plan approvable pending adoptionNot yet eligible: adopt the approved plan.
Wildrose cityCityExpired on 2022-11-02Williams County, ND Hazard Mitigation Plan 2017 (FEMA plan 104661)2017-11-022022-11-02-1,428FEMA tracker shows a plan approvable pending adoptionNot yet eligible: adopt the approved plan.
Williston cityCityExpired on 2022-11-02Williams County, ND Hazard Mitigation Plan 2017 (FEMA plan 104661)2017-11-022022-11-02-1,428FEMA 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 2026-06-30countWhy this hazard can be left outNRI Not Applicable, no declaration and no Storm Events record since 1996Storm Events coverage note
1Cold WaveRelatively HighRelatively High$9,394$685,700$9,963,968$10,659,06232
2Inland FloodingRelatively LowRelatively Low$7,551,626$183$22$7,551,83112
3TornadoRelatively LowRelatively Low$1,062,304$1,628$868,158$1,932,0906
4Winter WeatherVery HighVery High$761,320$175$660,426$1,421,92088
5Ice StormRelatively HighRelatively High$755,967n/a$173,195$929,1621
6HailRelatively LowRelatively Moderate$739,277$82,041$71,354$892,672204
7Strong WindRelatively LowRelatively Moderate$186,692$39,974$373,433$600,098193Includes 55 High Wind records (a NOAA non-thunderstorm wind type, outside NRI's Strong Wind definition).
8WildfireRelatively LowRelatively Low$431,618$33$15,444$447,0942
9LightningRelatively LowRelatively Low$21,875n/a$212,013$233,8883
10Heat WaveVery LowVery Low$1,159under $1$92,559$93,7191
11DroughtRelatively LowRelatively Lown/a$92,545n/a$92,54522
12EarthquakeVery LowVery Low$27,812n/a$5,438$33,249Storm Events does not record earthquakes.
13LandslideVery LowVery Low$631n/a$97$7280Declared 1 time; no Storm Events record of this type.
HurricaneNot ApplicableNot Applicable0NRI rates hurricane Not Applicable for this county, and no counted federal declaration for this county names it (EM-3247-ND 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 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: avalanche, coastal flooding, tsunami and volcanic activity. That is the evidence for leaving them out of the plan.

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

Supports FEMA checklist item B1-b: hazard location

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

Inland Flooding: The FEMA Flood Insurance Rate Map (FIRM) is the required location source for flooding. See the FEMA Flood Map Service Center (https://msc.fema.gov) for this county.

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

Source: 5

HazardHighest-rated census tractsNRI risk rating, score 0 to 100
Earthquaketract 9534 (Very Low, 23.2); tract 9535 (Very Low, 22.4); tract 9536 (Very Low, 21.2)
Hurricaneno tract has a National Risk Index rating for this hazard
Landslidetract 9536 (Relatively Low, 89.5); tract 9535 (Relatively Low, 81.9); tract 9534 (Very Low, 55.2)
Tornadotract 9537.01 (Relatively High, 87.0); tract 9536 (Relatively High, 82.0); tract 9535 (Relatively High, 78.1)
Wildfiretract 9536 (Relatively High, 96.8); tract 9537.01 (Relatively Moderate, 91.7); tract 9535 (Relatively Moderate, 90.9)

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 9534 is Census Tract 9534). 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
Cold/Wind Chill, Extreme Cold/Wind Chillwind chill32 records, 1996 to 2025 (32 zone-level)1 day to 11 days (median 2.5 days); 28 with a recorded value11 consecutive days, 2021-02-05 to 2021-02-15, zone-levelCountywide (zone-level records).Wind chill: in event narratives only (local data needed).
Frost/Freeze (outside NRI's Cold Wave definition)crop damage0Temperature: in event narratives only (local data needed).
DroughtU.S. Drought Monitor scale (D0 to D4)22 records, 2021 to 2025 (22 zone-level)211 days to 428 days (median 319.5 days); 2 with a recorded value428 days (about 14.1 months), 2021-03-16 to 2022-05-17, a run of 15 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)231 records, 1957 to 20260.75 in to 3 in (median 1 in); 231 with a recorded value3 in hail, 2022-07-18Hail, 2021-06-10, $1,000,000 property; $0 crops (2021 dollars)Event records naming jurisdictions in the plan: Williston city (51 records), Ray city (20 records), Epping city (12 records), Tioga city (12 records), Grenora city (11 records), Alamo city (10 records), Wildrose city (4 records).
Excessive Heat, Heatheat index (in event narratives)1 record, 2011 (1 zone-level)4 days; 1 with a recorded value4 consecutive days, 2011-07-16 to 2011-07-19, zone-levelCountywide (zone-level records).Heat index: in event narratives only (local data needed).
Hurricane, Tropical Storm, Tropical DepressionSaffir-Simpson0Storm Events files every zone of a storm's episode under the storm's type; flooding from the storm is filed as Flood or Flash Flood records.
Ice StormSperry-Piltz ice scale (local data)1 record, 1996 (1 zone-level)No damage reported in 1 record.Countywide (zone-level records).Ice thickness: in event narratives only (local data needed).
Flash Flood, Flood, Lakeshore Flooddamage and flood days (flood depth: FIRM)12 records, 1998 to 2021 (2 zone-level)Flash Flood, 2021-06-10, $800,000 property; $0 crops (2021 dollars)Event records naming jurisdictions in the plan: Grenora city (2 records), Alamo city (1 record). 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)0Physical measure: in event narratives only (local data needed).
Lightningannualized frequency (the measure FEMA's Local Mitigation Planning Handbook names)3 records, 1997 to 2010Lightning, 2010-07-29, $25,000 property; $0 crops (2010 dollars)Event records naming jurisdictions in the plan: Williston city (2 records), Tioga city (1 record).Storm Events lists lightning with damage or casualties; physical measure in event narratives only (local data needed).
High Wind and Strong Wind (outside NRI's Strong Wind definition)wind speed (kt and mph)55 records, 1999 to 2026 (55 zone-level)34 kt (39 mph) to 81 kt (93 mph) (median 52 kt (60 mph)); 55 with a recorded value81 kt (93 mph) measured gust, High Wind, 2021-01-13; NWS zone NDZ009Countywide (zone-level records).
Thunderstorm Windwind speed (kt and mph)185 records, 1960 to 202650 kt (58 mph) to 98 kt (113 mph) (median 56 kt (64 mph)); 167 with a recorded value98 kt (113 mph), measurement type not recorded, Thunderstorm Wind, 1998-07-05Thunderstorm Wind, 2014-09-03, $1,000,000 property; $500,000 crops (2014 dollars)Event records naming jurisdictions in the plan: Williston city (27 records), Tioga city (18 records), Ray city (17 records), Alamo city (5 records), Grenora city (5 records), Epping city (3 records), Wildrose city (1 record).
TornadoEnhanced Fujita (Fujita before Feb 2007)25 records, 1953 to 2025F/EF0 to F/EF3 (median F/EF0); 22 with a recorded valueF3 tornado, 1974-07-11, 33 yd wide, $2,500 property; crops not recorded (1974 dollars)Tornado, 1977-05-17, $250,000 property; crops not recorded (1977 dollars)Event records naming jurisdictions in the plan: Wildrose city (2 records), Williston city (2 records), Alamo city (1 record), Epping city (1 record), Tioga 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).
Wildfireacres burned (local data)2 records, 2012 to 2024 (2 zone-level)Wildfire, 2024-10-05, $12,000,000 property; $8,000,000 crops (2024 dollars), 2 direct deaths, 8 direct injuries (reported for the zone); NWS zone NDZ009Countywide (zone-level records).Acres burned: in event narratives only (local data needed).
Winter Storm, Heavy Snow, Blizzard, Lake-Effect Snow, Winter Weather, Sleetnone in data (snowfall: local data)88 records, 1996 to 2026 (88 zone-level)Blizzard, 2022-04-23, $15,000,000 property; $0 crops (2022 dollars); NWS zone NDZ009Countywide (zone-level records).Snow depth: in event narratives only (local data needed).

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

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

Supports FEMA checklist item B1-d: previous occurrences

Federal declarations for this county: 20 declarations covering 17 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
2026-09-012026-06-07DR-4934-NDMajor disasterSevere Storms, Straight-Line Winds, and TornadoesStrong Wind; Tornadonot yet in FEMA's PA summaries (they cover declarations through 2026-06-30)new since last plan; within last 5 years
2024-12-242024-10-05DR-4852-NDMajor disasterWildfires and Straight-Line WindsWildfire (primary); also designated: Strong Wind$2,926,506.05new since last plan; within last 5 years
2022-07-132022-04-22DR-4660-NDMajor disasterSevere Winter Storm and FloodingInland Flooding; Winter Weather$16,235,460.33new since last plan; within last 5 years
2021-09-012021-06-07DR-4613-NDMajor disasterSevere Storm, Straight-Line Winds, and FloodingInland Flooding; Strong Wind$1,568,956.63new since last plan
2020-04-012020-01-20DR-4509-NDMajor disasterCOVID-19 PandemicNon-natural, not counted$32,725.29new since last plan
2020-03-132020-01-20EM-3477-NDEmergencyCOVID-19Non-natural, not countedno Public Assistance recordednew since last plansame incident as DR-4509
2011-05-202011-04-29DR-1986-NDMajor disasterSevere Winter StormWinter Weather$4,145,736.64
2011-05-102011-02-14DR-1981-NDMajor disasterFloodingInland Flooding$911,439.71
2009-03-242009-03-13DR-1829-NDMajor disasterSevere Storms and FloodingInland Floodingno Public Assistance recorded
2005-09-132005-08-29EM-3247-NDEmergencyHurricane Katrina EvacuationHurricane: evacuation support, not a local hazard event; not countedno Public Assistance recorded
2004-04-022004-01-23EM-3196-NDEmergencySnowWinter Weather$45,984.74
2000-12-292000-11-01DR-1353-NDMajor disasterSevere Winter Storms and TornadoesTornado (primary); also designated: Winter Weather$24,653.25
1999-06-081999-03-01DR-1279-NDMajor disasterSevere Storms, Flooding, Snow, Ice, Ground Saturation, Lanslides, Mudslides, and TorInland Flooding (primary); also designated: Landslide, Tornado$200,040.99
1997-04-071997-02-28DR-1174-NDMajor disasterSevere Flooding,Severe Winter Storms, Snowmelt, Spring RainsInland Flooding (primary); also designated: Wildfire, Winter Weatherno Public Assistance recorded
1997-01-121997-01-03DR-1157-NDMajor disasterSevere Winter Storms and Blizzard ConditionsWinter Weatherno Public Assistance recorded
1994-07-011994-03-05DR-1032-NDMajor disasterSevere Storms, FloodingInland Floodingno Public Assistance recorded
1993-07-261993-06-22DR-1001-NDMajor disasterSevere Storms & FloodingInland Floodingno Public Assistance recorded
1979-04-261979-04-26DR-581-NDMajor disasterSevere Storms, Snowmelt & FloodingInland Floodingno Public Assistance recorded
1976-04-161976-04-16DR-501-NDMajor disasterFloodingInland Floodingno Public Assistance recorded
1969-04-181969-04-18DR-256-NDMajor disasterFloodingInland 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
2000-06-272000-04-05DR-1334-NDMajor disasterSevere Storms, Flooding and Ground SaturationInland Flooding
1957-06-221957-06-22DR-79-NDMajor disasterTornadoTornado

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: 3 rows, $964,911.20

Sources: 2, 3

FEMA numberDeclaredTitleApplicantPA obligatedfederal share obligated, nominal dollars
DR-4565-ND2020-10-02Severe Storms and FloodingMountrail-Williams Electric Cooperative$583,456.67
DR-1879-ND2010-02-26Severe Winter StormMountrail-Williams Electric Cooperative$84,285.41
DR-1515-ND2004-05-05Severe Storms, Flooding, and Ground SaturationMountrail-Williams Electric Cooperative$297,169.12

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 North Dakota county: 1 row, $23,693.61; listed on the North Dakota 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
Cold Wave32503001996 to 2026-06-30
Drought2222015001996 to 2026-06-30
Earthquake000000Storm Events does not record earthquakes; the USGS earthquake catalog is the source.
Hail23156025001955 to 2026-06-30
Heat Wave1000001996 to 2026-06-30
Hurricane0000001996 to 2026-06-30No recorded events, 1996 to 2026-06-30, NOAA NCEI Storm Events
Ice Storm1000001996 to 2026-06-30
Inland Flooding121001121996 to 2026-06-30
Landslide0000101996 to 2026-06-30No Storm Events records of this type; 1 federal declared incident (see declarations table)
Lightning3000001996 to 2026-06-30
Strong Wind24094250331955 to 2026-06-30Includes 55 High Wind records.
Tornado25201311950 to 2026-06-30
Wildfire2101211996 to 2026-06-30
Winter Weather8820514611996 to 2026-06-30

Notable Storm Events records

Sources: 1, 6, 7

DateEvent typeMagnitude or extentDamagenominal dollarsDeaths, injuriesdirect onlyLocationFlagsWhy listed
2024-10-05Wildfire$12,000,000 property; $8,000,000 crops, reported for the zone (2024 dollars)2, 8NWS zone NDZ009 (WILLIAMS), zone-levelnew since last plan; within last 5 yearsdeaths or injuries recorded
2022-07-18Hail3 in$500,000 property; $0 crops (2022 dollars)0, 0WILLISTONnew since last plan; within last 5 yearsB1-c worst recorded: Hail
2022-04-23Blizzard$15,000,000 property; $0 crops, reported for the zone (2022 dollars)0, 0NWS zone NDZ009 (WILLIAMS), zone-levelnew since last plan; within last 5 yearsB1-c worst recorded: Winter Storm, Heavy Snow, Blizzard, Lake-Effect Snow, Winter Weather, Sleet
2021-06-10Flash Flood$800,000 property; $0 crops (2021 dollars)0, 0(ISN)SLOULIN FLD WIL to SPRING BROOKnew since last planB1-c worst recorded: Flash Flood, Flood, Lakeshore Flood
2021-02-05Extreme Cold/Wind Chill$0 property; $0 crops, reported for the zone (2021 dollars)0, 0NWS zone NDZ009 (WILLIAMS), zone-levelnew since last planB1-c worst recorded: Cold/Wind Chill, Extreme Cold/Wind Chill
2021-01-13High Wind81 kt (93 mph) measured gust$50,000 property; $0 crops, reported for the zone (2021 dollars)0, 0NWS zone NDZ009 (WILLIAMS), zone-levelnew since last planB1-c worst recorded: High Wind and Strong Wind
2011-07-16Excessive Heat$0 property; $0 crops, reported for the zone (2011 dollars)0, 0NWS zone NDZ009 (WILLIAMS), zone-levelB1-c worst recorded: Excessive Heat, Heat
2010-07-29Lightning$25,000 property; $0 crops (2010 dollars)0, 0WILLISTONB1-c worst recorded: Lightning
1999-01-01Winter Stormdamage not reported2, 0NWS zone NDZ009 (WILLIAMS), zone-leveldeaths or injuries recorded
1998-07-05Thunderstorm Wind98 kt (113 mph), measurement type not recordeddamage not reported0, 0EPPINGB1-c worst recorded: Thunderstorm Wind
1990-06-26Thunderstorm Wind61 kt (70 mph), measurement type not recordeddamage not recorded (pre-1996 record)1, 1location not recordeddeaths or injuries recorded
1974-07-11TornadoF3, 33 yd wide$2,500 property; crops not recorded (1974 dollars)0, 0location not recordedB1-c worst recorded: Tornado

The full list is in the Excel file, sheet "B1-d Storm Events history" (657 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
Cold Wave18.7event-days per yearabout 18.7 days per yearLikely (from Storm Events: 15 of 30 years)event-days in 15 of 30 years, 1996 to 2025 (50%)3552005-11-12 to 2024-11-12 (19 years)countywide
Drought28.6event-days per yearabout 28.6 days per yearLikely (from Storm Events: 4 of 30 years)event-days in 4 of 30 years, 1996 to 2025 (13.3%)9312000 to 2025 (25.25 years; D3 and D4 only)countywide
Earthquake0.000098annual probability at a locationchance a given location in the county has at least minor-damage shaking in a year: 0.0098%not shownmodeledsee B1-fNo descriptor (Storm Events does not record earthquakes).
Hail1.62events per yearabout 1.62 per yearHighly likelyFEMA annualized frequency (modeled)63.3 (modeled)1986 to 2023 (38 years)countywide
Heat Wave0.79event-days per yearabout 0.79 days per yearPossible (from Storm Events: 1 of 30 years)event-days in 1 of 30 years, 1996 to 2025 (3.33%)122005-11-12 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 Storm0.488event-days per yearabout 0.488 days per yearPossible (from Storm Events: 1 of 30 years)event-days in 1 of 30 years, 1996 to 2025 (3.33%)331946-12-31 to 2014-02-12 (67 years)countywide
Inland Flooding0.393event-days per yearabout 0.393 days per yearLikely (from Storm Events: 7 of 30 years)event-days in 7 of 30 years, 1996 to 2025 (23.3%)111996 to 2023 (28 years)see B1-f
Landslide0.359events per year (modeled)about 1 in 3 yearsLikelyFEMA annualized frequency (modeled)not shownmodeledsee B1-f
Lightning26.4days per year with a strikeabout 26.4 days per yearHighly likelyFEMA annualized frequency (modeled)not shown1995 to 2023 (29 years; CONUS)countywide
Strong Wind1.07events per yearabout 1.07 per yearHighly likelyFEMA annualized frequency (modeled)411986 to 2023 (38 years)countywide
Tornado0.301events per yearabout 1 in 3 yearsLikelyFEMA annualized frequency (modeled)not shown1950 to 2023 (EF2+); 1986 to 2023 (EF0-1)see B1-f
Wildfire0.000568annual probability at a locationchance a given location in the county burns in a year: 0.0568%Possible (from Storm Events: 2 of 30 years)Storm Events records in 2 of 30 years, 1996 to 2025 (6.67%)not shownmodeledsee B1-fDescriptor from Storm Events, not NRI.
Winter Weather16.4event-days per yearabout 16.4 days per yearHighly likely (from Storm Events: 28 of 30 years)event-days in 28 of 30 years, 1996 to 2025 (93.3%)3112005-11-12 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 2025133304.43
Hail2.00 in+1996 to 20259300.3
Thunderstorm Wind (counted as NRI Strong Wind)50-64 kt1996 to 2025106303.53
Thunderstorm Wind (counted as NRI Strong Wind)65 kt+1996 to 202524300.8
Thunderstorm Wind (counted as NRI Strong Wind)unmeasured or below 50 kt1996 to 20250300
TornadoEF0-11996 to 20254300.133
TornadoEF2-31996 to 20250300
TornadoEF4-51996 to 20250300
Tornadounrated (EFU)1996 to 20252300.0667

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
Cold Wave8 of 894.098.899.8Very High 7, Relatively High 1
Drought5 of 873.489.792.4Relatively Moderate 1, Relatively Low 2, Very Low 2, No Rating 3
Earthquake8 of 86.110.223.2Very Low 8
Hail8 of 874.389.894.6Relatively High 4, Relatively Moderate 4
Heat Wave8 of 84.99.330.1Relatively Low 2, Very Low 6
Hurricane0 of 8Not Applicable 8
Ice Storm8 of 890.097.198.6Very High 4, Relatively High 3, Relatively Moderate 1
Inland Flooding8 of 814.968.184.7Relatively High 1, Relatively Moderate 5, Relatively Low 1, Very Low 1
Landslide7 of 811.931.589.5Relatively Low 2, Very Low 5, No Rating 1
Lightning8 of 845.667.892.0Relatively High 3, Relatively Moderate 4, Relatively Low 1
Strong Wind8 of 858.784.292.0Relatively High 5, Relatively Moderate 3
Tornado8 of 852.475.087.0Relatively High 5, Relatively Moderate 2, Relatively Low 1
Wildfire7 of 872.589.796.8Relatively High 1, Relatively Moderate 3, Relatively Low 3, No Rating 1
Winter Weather8 of 898.599.9100.0Very High 8

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
Williams CountyCountyExpired on 2022-11-02FMA RL 0, SRL 0; any 0$1,054,228.560 total; 0 since its planIncludes $13,511.19 for declarations not counted as hazard incidents (DR-4509-ND).
Alamo cityCityExpired on 2022-11-02$1,65017 total; 6 since its planNo NFIP community ID on this jurisdiction's plan row.
Epping cityCityExpired on 2022-11-02FMA RL 0, SRL 0; any 0$5,377.2816 total; 6 since its plan
Grenora cityCityExpired on 2022-11-02FMA RL 0, SRL 0; any 0$1,254.6618 total; 5 since its plan
Ray cityCityExpired on 2022-11-02FMA RL 0, SRL 0; any 0no Public Assistance recorded37 total; 16 since its plan
Tioga cityCityExpired on 2022-11-02FMA RL 0, SRL 0; any 0$4,477.3732 total; 13 since its plan
Wildrose cityCityExpired on 2022-11-02FMA RL 0, SRL 0; any 0$113,238.237 total; 2 since its plan
Williston cityCityExpired on 2022-11-02FMA RL 0, SRL 0; any 0$1,556,534.8982 total; 16 since its planIncludes $8,565.15 for declarations not counted as hazard incidents (DR-4509-ND).

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 2017-11-02county-coded records, property plus crops, nominal dollarsZone-level damage since planproperty plus crops, reported for the zonePublic Assistance since plannominal dollars; see noteNote
Cold Wave$18,983,657,607$169,792,81440,917$9,394$685,700$9,963,968under 0.0001%$0
Droughtn/a$107,946,593n/an/a$92,545n/a0.0857% (agriculture)$0NRI has no building exposure for this hazard; agriculture shown
Earthquake$35,460,834,168n/a40,950$27,812n/a$5,438under 0.0001%
Hail$18,983,657,607$169,792,81440,917$739,277$82,041$71,3540.00389%$1,760,000
Heat Wave$18,983,657,607$169,792,81440,917$1,159under $1$92,559under 0.0001%
HurricaneNot Applicable in NRI for this county
Ice Storm$18,983,657,607n/a40,917$755,967n/a$173,1950.00398%
Inland Flooding$18,977,452,040$22,828289$7,551,626$183$22n/a (see note)$800,000$17,804,416.96NRI 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$185,411,715n/a193$631n/a$970.00034%
Lightning$18,983,657,607n/a40,917$21,875n/a$212,0130.000115%
Strong Wind$18,983,657,607$169,792,81440,917$186,692$39,974$373,4330.000983%$870,000$50,000$4,495,462.68Storm Events damage since the plan includes 1 zone-level High Wind record ($50,000): a NOAA non-thunderstorm wind type, outside NRI's Strong Wind definition.
Tornado$18,983,657,607$169,792,81440,917$1,062,304$1,628$868,1580.0056%$0no Public Assistance recorded (1 declaration)
Wildfire$2,152,415,315$20,361,5946,172$431,618$33$15,4440.0201%$20,000,000$2,926,506.05
Winter Weather$18,983,657,607$169,792,81440,917$761,320$175$660,4260.00401%$15,000,000$16,235,460.33

Totals since 2017-11-02 (Storm Events through 2026-06-30): 130 county-coded records, 130 with a damage value recorded (including $0), $3,430,000; 71 zone-level records, 71 with a damage value recorded (including $0), $35,050,000 reported for the zone; Public Assistance: $20,730,923.01 on 4 counted declarations, 3 of them with Public Assistance.

FEMA does not split Public Assistance by hazard. A declaration mapped to several hazards is listed under each of them with its full amount, so the per-hazard column does not add up to the total; the unit total counts each declaration once.

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

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

County context

Source: 5

MeasureValue
Population40,917
Building value (total, not at risk)$18,983,657,607
Agriculture value (total, not at risk)$169,792,814
NRI risk rating (all hazards)Relatively Low
Expected annual loss, buildings and agriculture, all hazards$12,451,954
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)$12,436,106
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 definition0Severe repetitive loss, NFIP insurance definition0

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

Repeat-flood properties: county total and NFIP communities

Sources: 1, 4

ScopeRL, FMApropertiesSRL, FMApropertiesRL, NFIPpropertiesSRL, NFIPpropertiesAny categorypropertiesMitigatedpropertiesCurrently insuredproperties
County total0000000

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

Sources: 1, 4

JurisdictionNFIP community IDRL, FMApropertiesSRL, FMApropertiesRL, NFIPpropertiesSRL, NFIPpropertiesAny categorypropertiesMitigatedpropertiesCurrently insuredproperties
Williams County3801460000000
Epping city3803730000000
Grenora city3801770000000
Ray city3802470000000
Tioga city3801470000000
Wildrose city3802110000000
Williston city3803190000000

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

Jurisdiction rows are whole NFIP communities and need not add up to the county total: a community that extends into another county is counted in full on each jurisdiction row, while the county table counts only its part in this county.

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

Sources: 1, 4

FMA RL and FMA SRL are the Flood Mitigation Assistance definitions (44 CFR 77.2), the ones the FEMA Local Mitigation Planning Policy Guide cites. NFIP repetitive loss (the FEMA insurance definition) is 2 or more claims over $1,000 in 10 years, and a property can leave that group once it is mitigated. Also shown: NFIP severe repetitive loss, any category, mitigated and currently insured. The Methods page gives the OpenFEMA field details.

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

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

Exact counts; no count suppression.

Sources

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

  1. FEMA, OpenFEMA HazardMitigationPlanStatuses v1, version 2026-09-29T134039Z, pulled 2026-09-30, https://www.fema.gov/api/open/v1/HazardMitigationPlanStatuses (API)
  2. FEMA, OpenFEMA DisasterDeclarationsSummaries v2, version 2026-09-29T162832Z, pulled 2026-09-30, https://www.fema.gov/api/open/v2/DisasterDeclarationsSummaries (API)
  3. FEMA, OpenFEMA PublicAssistanceFundedProjectsSummaries v1, version 2026-09-29T150754Z, pulled 2026-09-30, https://www.fema.gov/api/open/v1/PublicAssistanceFundedProjectsSummaries (API)
  4. FEMA, OpenFEMA NfipMultipleLossProperties v1, version 2026-08-04T164045Z, pulled 2026-09-30, https://www.fema.gov/api/open/v1/NfipMultipleLossProperties (API)
  5. FEMA, FEMA National Risk Index 1.20.0 (December 2025), county and census tract tables, version 1.20.0, pulled 2026-09-30, https://www.fema.gov/about/reports-and-data/openfema/nri/v120/NRI_Table_Counties.zip (download, 25 MB), https://www.fema.gov/about/reports-and-data/openfema/nri/v120/NRI_Table_CensusTracts.zip (download, 635 MB)
  6. NOAA NCEI, NOAA NCEI Storm Events Database, details files (csvfiles v1.0), version c20260918, pulled 2026-09-30, https://www.ncei.noaa.gov/pub/data/swdi/stormevents/csvfiles/
  7. NOAA National Weather Service, NWS county-public forecast zones correlation file, version bp03mr20 to bp16ap26 (11 files; newest bp16ap26), pulled 2026-09-30, https://www.weather.gov/gis/ZoneCounty
  8. U.S. Census Bureau, Census 2024 Gazetteer, 2020 place by county, CT county-to-cousub crosswalk, version 2024-gazetteer, pulled 2026-09-30, https://www2.census.gov/geo/docs/maps-data/data/gazetteer/2024_Gazetteer/2024_Gaz_counties_national.zip, https://www2.census.gov/geo/docs/maps-data/data/gazetteer/2024_Gazetteer/2024_Gaz_cousubs_national.zip, https://www2.census.gov/geo/docs/maps-data/data/gazetteer/2024_Gazetteer/2024_Gaz_place_national.zip, https://www2.census.gov/geo/docs/maps-data/data/gazetteer/2024_Gazetteer/2024_Gaz_unsd_national.zip, https://www2.census.gov/geo/docs/maps-data/data/gazetteer/2024_Gazetteer/2024_Gaz_elsd_national.zip, https://www2.census.gov/geo/docs/maps-data/data/gazetteer/2024_Gazetteer/2024_Gaz_scsd_national.zip, https://www2.census.gov/geo/docs/reference/codes2020/national_place_by_county2020.txt, https://www2.census.gov/geo/docs/reference/ct_change/ct_cou_to_cousub_crosswalk.xlsx (used to match place names and codes; no table prints its values)

What this packet is and what the plan adds

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

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

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

OpenFEMA disclaimer

This product uses the Federal Emergency Management Agency's OpenFEMA API, but is not endorsed by FEMA. The Federal Government or FEMA cannot vouch for the data or analyses derived from these data after the data have been retrieved from the Agency's website(s).

Reuse, citation and corrections

Reuse and citation: Hazard Plain text and tables are licensed under Creative Commons Attribution 4.0 International (CC BY 4.0, https://creativecommons.org/licenses/by/4.0/); credit Hazard Plain and the release. The underlying federal data are public domain; OpenFEMA data are also subject to the OpenFEMA terms and conditions.

Cite this: Hazard Plain (2026). Williams County, ND: risk-assessment baseline packet, release 2026-10 (data as of 2026-09-30; County FIPS 38105). Automated baseline. https://hazardplain.org/nd/38105/ Built from FEMA OpenFEMA, the FEMA National Risk Index and NOAA NCEI Storm Events; source versions in the packet's Sources list.

Corrections: to report an error, name the packet, the table and what your records show. Contact: [email protected]

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