Carbon County, UT

Supports FEMA checklist item B1-a Hazard identification

15 of the 18 National Risk Index hazards apply here.

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.

Highest expected annual loss (NRI, modeled): Inland Flooding, Earthquake and Lightning.

Not covered by NRI (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 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

• Avalanche, Earthquake, Hurricane, Landslide, Tornado, Volcanic Activity and Wildfire vary within the county; the packet lists the highest-rated census tracts for each.
• Cold Wave, Drought, Hail, Heat Wave, Ice Storm, Lightning, Strong Wind and Winter Weather: affects the whole county; national data give no location within it.
• 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.

Supports FEMA checklist item B1-c Hazard extent

Storm Events records for 12 of the 20 NOAA event-type groups mapped to the 18 hazards, with the scale, observed range and worst recorded event for each; the others say which local data are needed.

Worst recorded tornado, hail and thunderstorm wind (the three event types on record since the 1950s; the packet has every group):

• Hail: 2 in hail, 2013-09-17; same size also recorded on 2002-08-29
• Thunderstorm Wind: 63 kt (72 mph), measurement type not recorded, Thunderstorm Wind, 1997-09-19
• Tornado: EF0 tornado, 2010-07-26, 0.12 mi within this county, 15 yd wide, $25,000 property; $0 crops (2010 dollars)

Supports FEMA checklist item B1-d Previous occurrences

Federal declarations for this area: 5 declarations covering 2 separate hazard incidents counted in this packet; each with type, dates and county Public Assistance dollars.

New since the last plan (approved 2026-01-06): none.

Hazards with no Storm Events record and no federal declaration are stated as such (6 of 18).

Storm Events history: 265 records (notable ones in the PDF, all of them in the Excel file).

Supports FEMA checklist item B1-e Probability of future events

FEMA annualized frequency (modeled) for each hazard, with a descriptor from a scale defined in the packet.

• Highly likely: Landslide, Lightning and Winter Weather
• Likely: Hail, Inland Flooding and Strong Wind
• Possible: Avalanche, Cold Wave, Heat Wave, Tornado and Wildfire
• Unlikely: Earthquake and Volcanic Activity

Historical frequency by intensity band (tornado, hail, wind): 9 bands from Storm Events.

Supports FEMA checklist item B1-f Hazards that vary across jurisdictions

Range of census tract risk scores within the area for 16 of the 18 hazards (5 tracts; rated tracts only).

6 jurisdictions: plan clock, repeat-flood count, Public Assistance dollars and event records naming the place (starting figures from federal data).

Supports FEMA checklist items B2-a and B2-b Vulnerability and potential impacts

The packet's table gives county-level starting figures; the plan describes impacts for each jurisdiction and its own assets.

Storm Events damage since 2026-01-06: $0 in county-coded records (1 record); $80,000 reported for the zone (1 zone record). Data through 2026-06-30; nominal dollars.

Local data needed

To gather:

• 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

Supports FEMA checklist item B2-a Vulnerability (county context)

Population 20,381; building value $3,087,052,516 and agriculture value $8,317,160 (total, not at risk).

National Risk Index rating Very Low; social vulnerability Relatively Low; community resilience Relatively Moderate.

Supports FEMA checklist item B2-c Repetitive loss properties

Repetitive-loss properties, FMA definition (44 CFR 77.2): 0 repetitive loss, 0 severe repetitive loss. NFIP insurance definition: 0 and 0.

Mitigated 0; insured 0; NFIP data as of 2026-08-02. Counts by occupancy group and for each jurisdiction are in the packet.