Hazard Plain Automated baseline

Summit County, UT

Risk-assessment baseline packet

County FIPS:
49043
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 2027-05-17. Plan: Mountainland AOG, UT Hazard Mitigation Plan 2022 (FEMA plan 108125), approved 2022-05-18.

Since the plan was approved on 2022-05-18: 1 new hazard declaration (1 incident) and 103 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 ($11,942,905 a year), Wildfire ($10,689,198) and Avalanche ($10,307,221).

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 2027-05-17
Plan:
Mountainland AOG, UT Hazard Mitigation Plan 2022 (FEMA plan 108125)
Approved:
2022-05-18
Days to expiry:
229
Update underway:
none recorded in FEMA's plan tracker

What changed since your last plan (approved 2022-05-18)

New federal declarations:
1 new hazard declaration (1 incident): FM-5665-UT (Rocky Canyon Fire)
Storm Events records since approval:
103 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 expiry
Summit CountyCountyApproved, expires 2027-05-17Mountainland AOG, UT Hazard Mitigation Plan 2022 (FEMA plan 108125)2022-05-182027-05-17229
Francis townTownApproved, expires 2027-05-17Mountainland AOG, UT Hazard Mitigation Plan 2022 (FEMA plan 108125)2022-05-182027-05-17229
Henefer townTownApproved, expires 2027-05-17Mountainland AOG, UT Hazard Mitigation Plan 2022 (FEMA plan 108125)2022-05-182027-05-17229
Kamas cityCityApproved, expires 2027-05-17Mountainland AOG, UT Hazard Mitigation Plan 2022 (FEMA plan 108125)2022-05-182027-05-17229
Oakley cityCityApproved, expires 2027-05-17Mountainland AOG, UT Hazard Mitigation Plan 2022 (FEMA plan 108125)2022-05-182027-05-17229
Park City cityCityApproved, expires 2027-05-17Mountainland AOG, UT Hazard Mitigation Plan 2022 (FEMA plan 108125)2022-05-182027-05-17229
South Summit School DistrictSchool/School DistrictApproved, expires 2027-05-17Mountainland AOG, UT Hazard Mitigation Plan 2022 (FEMA plan 108125)2022-05-182027-05-17229

Plan 108125 covers 35 other participants, named in the Excel file.

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

Supports FEMA checklist item B1-a: hazard identification

Hazards NRI does not cover (local data needed)

  • dam failure (incl. upstream dams)
  • levee failure
  • flash flood as its own subtype
  • ice jams
  • debris flows
  • erosion (riverine and coastal)
  • land subsidence and sinkholes
  • expansive soils

The 18 National Risk Index hazards, ranked by expected annual loss (EAL)

Sources: 5, 6

Rank by EALHazardNRI risk ratingEAL ratingEAL buildingsmodeled dollars per yearEAL agriculturemodeled dollars per yearCost of expected deaths and injuriesFEMA's dollar value per year, not property damageEAL total (see note)modeled dollars per yearStorm Events records, 1996 to 2026-06-30countWhy this hazard can be left outNRI Not Applicable, no declaration and no Storm Events record since 1996Storm Events coverage note
1Inland FloodingRelatively LowRelatively Low$11,929,216$80$13,610$11,942,90510
2WildfireRelatively ModerateRelatively High$10,334,533$301$354,364$10,689,19811
3AvalancheVery HighVery High$1,997n/a$10,305,224$10,307,22174
4LightningRelatively HighRelatively High$7,128n/a$2,348,571$2,355,7004
5Strong WindRelatively ModerateRelatively Moderate$229,160$3,035$1,165,141$1,397,337126Includes 95 High Wind and 5 Strong Wind records (NOAA non-thunderstorm wind types, outside NRI's Strong Wind definition).
6EarthquakeVery LowRelatively Low$608,191n/a$61,339$669,531Storm Events does not record earthquakes.
7Winter WeatherRelatively HighRelatively High$84,652$204$502,617$587,474497
8TornadoVery LowVery Low$93,362$166$115,819$209,3470No recorded events in Storm Events since 1996 (data through 2026-06-30).
9LandslideRelatively ModerateRelatively Low$77,912n/a$63,295$141,2070Declared 2 times; no Storm Events record of this type.
10Cold WaveVery LowVery Low$379$1,117$100,648$102,1442
11Heat WaveVery LowVery Low$18$466$56,964$57,4490No recorded events in Storm Events since 1996 (data through 2026-06-30).
12HailVery LowVery Low$43,284$982$10,990$55,25610
13DroughtVery LowRelatively Lown/a$30,686n/a$30,6860Declared 1 time; no Storm Events record of this type.
14Ice StormVery LowVery Low$11,942n/a$2,887$14,8300No recorded events in Storm Events since 1996 (data through 2026-06-30).
15Volcanic ActivityVery LowVery Lowunder $1n/a$10$100No 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-3223-UT 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
Avalanchetract 9643.08 (Very High, 99.4); tract 9641.01 (Very High, 99.0); tract 9642.03 (Very High, 98.9)
Earthquaketract 9642.01 (Relatively Low, 61.2); tract 9642.02 (Relatively Low, 60.8); tract 9643.06 (Relatively Low, 60.4)
Hurricaneno tract has a National Risk Index rating for this hazard
Landslidetract 9642.03 (Relatively Moderate, 99.2); tract 9641.01 (Relatively Moderate, 99.1); tract 9641.04 (Relatively Moderate, 97.9)
Tornadotract 9643.08 (Relatively Low, 32.0); tract 9642.01 (Very Low, 28.7); tract 9643.06 (Very Low, 27.2)
Volcanic Activitytract 9642.01 (Very Low, 58.2); tract 9643.08 (Very Low, 57.7); tract 9643.06 (Very Low, 52.7)
Wildfiretract 9643.06 (Relatively High, 99.0); tract 9643.08 (Relatively High, 98.7); tract 9643.04 (Relatively High, 98.6)

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 9643.08 is Census Tract 9643.08). 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)74 records, 1998 to 2026 (74 zone-level)Avalanche, 2023-04-10, $100,000 property; $0 crops (2023 dollars); NWS zone UTZ111Countywide (zone-level records).
Cold/Wind Chill, Extreme Cold/Wind Chillwind chill2 records, 1998 to 2005 (2 zone-level)1 day to 4 days (median 2.5 days); 2 with a recorded value4 consecutive days, 1998-12-21 to 1998-12-24, 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)13 records, 1987 to 20260.75 in to 1.5 in (median 1 in); 13 with a recorded value1.5 in hail, 1990-09-25; same size also recorded on 1987-07-21Hail, 1998-05-21, $0 property; $200 crops (1998 dollars)Event records naming jurisdictions in the plan: Kamas city (2 records), Henefer town (1 record), Oakley city (1 record), Park City 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)10 records, 1997 to 2022 (4 zone-level)Flood, 2010-06-06, $5,000,000 property; $0 crops (2010 dollars)Event records naming jurisdictions in the plan: Oakley city (1 record). Zone-level records (4) 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)4 records, 2003 to 2012Lightning, 2003-07-19, $0 property; $0 crops (2003 dollars), 2 direct deaths, 3 direct injuriesNo 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)100 records, 1996 to 2024 (100 zone-level)47 kt (54 mph) to 129 kt (148 mph) (median 72 kt (83 mph)); 97 with a recorded value129 kt (148 mph) measured gust, High Wind, 2022-12-27; NWS zone UTZ110High Wind, 2016-02-18, $150,000 property; $0 crops (zone total, 2016 dollars)Countywide (zone-level records).
Thunderstorm Windwind speed (kt and mph)29 records, 1973 to 202645 kt (52 mph) to 63 kt (72 mph) (median 53 kt (61 mph)); 28 with a recorded value63 kt (72 mph) measured gust, Thunderstorm Wind, 2014-06-10Thunderstorm Wind, 2016-06-11, $75,000 property; $0 crops (2016 dollars)Event records naming jurisdictions in the plan: Park City city (3 records), Kamas city (2 records), Francis town (1 record), Henefer town (1 record).
TornadoEnhanced Fujita (Fujita before Feb 2007)0Before 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)11 records, 2007 to 2018 (11 zone-level)Wildfire, 2012-07-01, $9,000,000 property; $0 crops (2012 dollars); NWS zone UTZ008Countywide (zone-level records).
Winter Storm, Heavy Snow, Blizzard, Lake-Effect Snow, Winter Weather, Sleetnone in data (snowfall: local data)497 records, 1996 to 2026 (497 zone-level)Heavy Snow, 2023-04-01, $1,000,000 property; $0 crops (2023 dollars); NWS zone UTZ108Heavy Snow, 2024-02-06, $1,000,000 property; $0 crops (zone total, 2024 dollars)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: 10 declarations covering 7 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
2026-08-092026-08-09FM-5665-UTFire managementRocky Canyon FireWildfirenot yet in FEMA's PA summaries (they cover declarations through 2026-06-30)new since last plan; within last 5 years
2021-08-142021-08-14FM-5408-UTFire managementParleys Canyon FireWildfireno Public Assistance recordedin the 12 months before plan approval
2020-04-042020-01-20DR-4525-UTMajor disasterCOVID-19 PandemicNon-natural, not countedno Public Assistance recorded
2020-03-132020-01-20EM-3478-UTEmergencyCOVID-19Non-natural, not countedno Public Assistance recordedsame incident as DR-4525
2013-08-132013-08-13FM-5044-UTFire managementRockport Five FireWildfireno Public Assistance recorded
2011-08-082011-04-18DR-4011-UTMajor disasterFloodingInland Flooding$73,479.32
2005-09-052005-08-29EM-3223-UTEmergencyHurricane Katrina EvacuationHurricane: evacuation support, not a local hazard event; not countedno Public Assistance recorded
1984-08-171984-08-17DR-720-UTMajor disasterSevere Storms, Mudslides, Landslides & FloodingInland Flooding (primary); also designated: Landslideno Public Assistance recorded
1983-04-301983-04-13DR-680-UTMajor disasterSevere Storms, Landslides & FloodingInland Flooding (primary); also designated: Landslideno Public Assistance recorded
1977-01-201977-01-20EM-3024-UTEmergencyDroughtDroughtno 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.

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
Avalanche7424024001996 to 2026-06-30
Cold Wave2000001996 to 2026-06-30
Drought0000101996 to 2026-06-30No Storm Events records of this type; 1 federal declared incident (see declarations table)
Earthquake000000Storm Events does not record earthquakes; the USGS earthquake catalog is the source.
Hail13101001955 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 Flooding10101301996 to 2026-06-30
Landslide0000201996 to 2026-06-30No Storm Events records of this type; 2 federal declared incidents (see declarations table)
Lightning4000001996 to 2026-06-30
Strong Wind12925126001955 to 2026-06-30Includes 95 High Wind and 5 Strong Wind records.
Tornado0000001950 to 2026-06-30No recorded events, 1950 to 2026-06-30, NOAA NCEI Storm Events
Volcanic Activity0000001996 to 2026-06-30No recorded events, 1996 to 2026-06-30, NOAA NCEI Storm Events
Wildfire11000311996 to 2026-06-30
Winter Weather49752860001996 to 2026-06-30

Notable Storm Events records

Sources: 1, 6, 7

DateEvent typeMagnitude or extentDamagenominal dollarsDeaths, injuriesdirect onlyLocationFlagsWhy listed
2023-04-10Avalanche$100,000 property; $0 crops (zone total, 2023 dollars)0, 0NWS zone UTZ111 (WASATCH MOUNTAINS SOUTH OF I-80), zone-levelnew since last plan; within last 5 yearsB1-c worst recorded: Avalanche
2023-04-01Heavy Snow$1,000,000 property; $0 crops (zone total, 2023 dollars)0, 0NWS zone UTZ108 (WASATCH BACK), zone-levelnew since last plan; within last 5 yearsB1-c worst recorded: Winter Storm, Heavy Snow, Blizzard, Lake-Effect Snow, Winter Weather, Sleet
2022-12-27High Wind129 kt (148 mph) measured gust$0 property; $0 crops (zone total, 2022 dollars)0, 0NWS zone UTZ110 (WASATCH MOUNTAINS I-80 NORTH), zone-levelnew since last plan; within last 5 yearsB1-c worst recorded: High Wind and Strong Wind
2021-02-06Avalanche$0 property; $0 crops (zone total, 2021 dollars)4, 1NWS zone UTZ008 (WASATCH MOUNTAINS SOUTH OF I-80), zone-leveldeaths or injuries recorded
2014-06-10Thunderstorm Wind63 kt (72 mph) measured gust$0 property; $0 crops (2014 dollars)0, 0KIMBALL JCTB1-c worst recorded: Thunderstorm Wind
2012-07-01Wildfire$9,000,000 property; $0 crops (zone total, 2012 dollars)0, 0NWS zone UTZ008 (WASATCH MOUNTAINS SOUTH OF I-80), zone-levelB1-c worst recorded: Wildfire
2010-06-06Flood$5,000,000 property; $0 crops (2010 dollars)0, 0PEOA to MARIONB1-c worst recorded: Flash Flood, Flood, Lakeshore Flood
2007-06-29Wildfiredamage not reported3, 0NWS zone UTZ009 (WESTERN UINTA MOUNTAINS), zone-leveldeaths or injuries recorded
2003-12-26Avalanche$0 property; $0 crops (zone total, 2003 dollars)3, 0NWS zone UTZ008 (W SUMMIT T NW/SE SALT LAKE/WASATCH X SC/E UTAH/P X E JUAB/X NW SAN PETE), zone-leveldeaths or injuries recorded
2003-07-19Lightning$0 property; $0 crops (2003 dollars)2, 3CENTRAL PORTIONB1-c worst recorded: Lightning
1998-12-21Cold/Wind Chilldamage not reported0, 0NWS zone UTZ009 (C E SUMMIT/X NE WASATCH/N DUCHESNE), zone-levelB1-c worst recorded: Cold/Wind Chill, Extreme Cold/Wind Chill
1990-09-25Hail1.5 indamage not recorded (pre-1996 record)0, 0location not recordedB1-c worst recorded: Hail

The full list is in the Excel file, sheet "B1-d Storm Events history" (740 rows).

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

2 Fire Management declarations (1994-08-06 to 1994-08-06) FEMA filed as Statewide with no county; each names one local fire. Listed on the state page.

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
Avalanche1.53events per yearabout 1.53 per yearHighly likelyFEMA annualized frequency (modeled)461994 to 2023 (30 years)see B1-f
Cold Wave0.0689event-days per yearabout 0.0689 days per yearPossibleStorm Events event-days in 2 of 30 years, 1996 to 2025 (6.67%)1.312005-11-12 to 2024-11-12 (19 years)countywide
Drought75.2event-days per yearabout 75.2 days per yearStorm Events event-days in 0 of 30 years, 1996 to 2025 (0%)2,5412000 to 2025 (25.25 years; D3 and D4 only)countywideNo Storm Events drought record, 1996 to 2025
Earthquake0.00703annual probability at a locationchance a given location in the county has at least minor-damage shaking in a year: 0.703%not shownmodeledsee B1-fNo descriptor (Storm Events does not record earthquakes).
Hail0.237events per yearabout 1 in 4 yearsLikelyFEMA annualized frequency (modeled)9.0 (modeled)1986 to 2023 (38 years)countywide
Heat Wave0.0525event-days per yearabout 0.0525 days per yearStorm Events event-days in 0 of 30 years, 1996 to 2025 (0%)1.012005-11-12 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 Storm0.0149event-days per yearabout 0.0149 days per yearStorm Events event-days in 0 of 30 years, 1996 to 2025 (0%)01946-12-31 to 2014-02-12 (67 years)countywideNo Storm Events ice storm record, 1996 to 2025
Inland Flooding0.214event-days per yearabout 0.214 days per yearLikelyStorm Events event-days in 8 of 30 years, 1996 to 2025 (26.7%)61996 to 2023 (28 years)see B1-f
Landslide1.4events per year (modeled)about 1.4 per yearHighly likelyFEMA annualized frequency (modeled)not shownmodeledsee B1-f
Lightning43.1days per year with a strikeabout 43.1 days per yearHighly likelyFEMA annualized frequency (modeled)not shown1995 to 2023 (29 years; CONUS)countywide
Strong Wind0.701events per yearabout 0.7 per yearLikelyFEMA annualized frequency (modeled)271986 to 2023 (38 years)countywide
Tornado0.11events per yearabout 1 in 9 yearsLikelyFEMA 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
Wildfire0.00446annual probability at a locationchance a given location in the county burns in a year: 0.446%LikelyStorm Events records in 4 of 30 years, 1996 to 2025 (13.3%)not shownmodeledsee B1-f
Winter Weather51.3event-days per yearabout 51.3 days per yearHighly likelyStorm Events event-days in 30 of 30 years, 1996 to 2025 (100%)9742005-11-12 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 20254300.133
Hail2.00 in+1996 to 20250300
Thunderstorm Wind (counted as NRI Strong Wind)50-64 kt1996 to 202523300.767
Thunderstorm Wind (counted as NRI Strong Wind)65 kt+1996 to 20250300
Thunderstorm Wind (counted as NRI Strong Wind)unmeasured or below 50 kt1996 to 20251300.0333
TornadoEF0-11996 to 20250300
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
Avalanche12 of 1495.297.999.4Very High 7, Relatively High 5, Not Applicable 2
Cold Wave14 of 1416.120.525.6Relatively Low 9, Very Low 5
Drought8 of 1472.677.988.4Relatively Low 3, Very Low 5, No Rating 6
Earthquake14 of 1439.253.461.2Relatively Low 13, Very Low 1
Hail14 of 1426.034.347.3Relatively Low 5, Very Low 9
Heat Wave13 of 142.13.68.5Very Low 13, No Rating 1
Hurricane0 of 14Not Applicable 14
Ice Storm14 of 143.98.822.7Very Low 14
Inland Flooding14 of 1415.750.084.3Relatively High 2, Relatively Moderate 7, Relatively Low 5
Landslide14 of 1471.595.499.2Relatively Moderate 6, Relatively Low 7, Very Low 1
Lightning14 of 1448.798.899.8Very High 9, Relatively High 4, Relatively Low 1
Strong Wind14 of 1436.786.793.9Relatively High 8, Relatively Moderate 5, Relatively Low 1
Tornado14 of 1410.524.432.0Relatively Low 1, Very Low 13
Volcanic Activity14 of 1441.045.858.2Very Low 14
Wildfire14 of 1496.998.099.0Relatively High 14
Winter Weather14 of 1479.996.199.0Very High 8, Relatively High 6

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 plan
Summit CountyCountyApproved, expires 2027-05-17FMA RL 0, SRL 0; any 0$36,596.180 total; 0 since its plan
Francis townTownApproved, expires 2027-05-17FMA RL 0, SRL 0; any 0no Public Assistance recorded1 total; 0 since its plan
Henefer townTownApproved, expires 2027-05-17FMA RL 0, SRL 0; any 0no Public Assistance recorded2 total; 0 since its plan
Kamas cityCityApproved, expires 2027-05-17FMA RL 0, SRL 0; any 0$7,213.934 total; 1 since its plan
Oakley cityCityApproved, expires 2027-05-17FMA RL 0, SRL 0; any 0no Public Assistance recorded2 total; 0 since its plan
Park City cityCityApproved, expires 2027-05-17FMA RL 0, SRL 0; any 0$18,488.454 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 2022-05-18county-coded records, property plus crops, nominal dollarsZone-level damage since planproperty plus crops, reported for the zonePublic Assistance since plannominal dollars; see noteNote
Avalanche$1,882,252n/a10$1,997n/a$10,305,2240.106%$188,500
Cold Wave$12,640,876,759$32,885,14141,509$379$1,117$100,648under 0.0001%
Droughtn/a$3,038,934n/an/a$30,686n/a1.01% (agriculture)NRI has no building exposure for this hazard; agriculture shown
Earthquake$21,365,013,094n/a42,357$608,191n/a$61,3390.00285%
Hail$13,250,586,190$32,885,14142,322$43,284$982$10,9900.000327%$0
Heat Wave$10,670,961,657$30,797,17935,609$18$466$56,964under 0.0001%
HurricaneNot Applicable in NRI for this county
Ice Storm$13,250,586,190n/a42,322$11,942n/a$2,887under 0.0001%
Inland Flooding$13,236,735,146$4,062,313954$11,929,216$80$13,610n/a (see note)$1,000NRI 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$1,706,581,322n/a4,432$77,912n/a$63,2950.00457%
Lightning$13,250,586,190n/a42,322$7,128n/a$2,348,571under 0.0001%
Strong Wind$13,250,586,190$32,885,14142,322$229,160$3,035$1,165,1410.00173%$0$5,000Storm Events damage since the plan includes 1 zone-level High Wind record ($5,000): a NOAA non-thunderstorm wind type, outside NRI's Strong Wind definition.
Tornado$13,250,586,190$32,885,14142,322$93,362$166$115,8190.000705%
Volcanic Activity$13,250,586,190n/a42,322under $1n/a$10under 0.0001%
Wildfire$6,981,030,750$25,056,11325,006$10,334,533$301$354,3640.148%1 declaration not yet in FEMA's PA summaries (they cover declarations through 2026-06-30)
Winter Weather$13,250,586,190$32,885,14142,322$84,652$204$502,6170.000639%$2,580,000

Totals since 2022-05-18 (Storm Events through 2026-06-30): 13 county-coded records, 13 with a damage value recorded (including $0), $1,000; 90 zone-level records, 90 with a damage value recorded (including $0), $2,773,500 reported for the zone; Public Assistance: the 1 counted declaration is not yet in FEMA's PA summaries (they cover declarations through 2026-06-30).

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
Population42,322
Building value (total, not at risk)$13,250,586,190
Agriculture value (total, not at risk)$32,885,141
NRI risk rating (all hazards)Relatively Low
Expected annual loss, buildings and agriculture, all hazards$23,458,813
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)$15,101,479
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 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
Summit County4901340000000
Francis town4901990000000
Henefer town4901360000000
Kamas city4901370000000
Oakley city4901380000000
Park City city4901390000000

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 (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). Summit County, UT: risk-assessment baseline packet, release 2026-10 (data as of 2026-09-30; County FIPS 49043). Automated baseline. https://hazardplain.org/ut/49043/ 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]