Automated baseline from FEMA and NOAA data, release 2026-10.

Lewis and Clark County, MT

Risk-assessment baseline packet. County FIPS 30049. Release 2026-10, data as of 2026-09-30.

Summary

Plan status as of 2026-09-30: Approved, expires 2029-11-20. Plan: Western Montana Regional Hazard Mitigation Plan 2024 (FEMA plan 110263), approved 2024-11-21.

Since the plan was approved on 2024-11-21: no new hazard declaration and 86 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): Cold Wave ($12,893,215 a year), Inland Flooding ($12,360,093) and Earthquake ($3,795,774).

The packet's tables are organized by the items of FEMA's Local Mitigation Plan Review Tool, Element B (B1-a to B2-c); the summaries below follow the same order.

Download the packet

Full packet as a web page. File manifest (checksums, source versions).

Plan clock

Approved, expires 2029-11-20

Plan:
Western Montana Regional Hazard Mitigation Plan 2024 (FEMA plan 110263)
Approved:
2024-11-21
Days to expiry:
1,147

What changed since your last plan (approved 2024-11-21)

New federal declarations:
none
Storm Events records since approval:
86 records (data through 2026-06-30)
Repetitive loss now:
FMA RL 0, SRL 0 (44 CFR 77.2); any definition: 5
Repeat-flood change:
this release sets the baseline count.

Plan status for every jurisdiction listed in this county

4 jurisdictions. Each row is that jurisdiction's own plan clock. Notes include other approved plans FEMA lists for the same jurisdiction.

JurisdictionTypeStatusPlanApprovedExpiresDays to expirynegative = days since expiryNotes
Lewis and Clark CountyCountyApproved, expires 2029-11-20Western Montana Regional Hazard Mitigation Plan 2024 (FEMA plan 110263)2024-11-212029-11-201,147This jurisdiction approved 2025-06-06.
East Helena cityCityApproved, expires 2029-11-20Western Montana Regional Hazard Mitigation Plan 2024 (FEMA plan 110263)2024-11-212029-11-201,147This jurisdiction approved 2025-08-29.
Helena cityCityApproved, expires 2029-11-20Western Montana Regional Hazard Mitigation Plan 2024 (FEMA plan 110263)2024-11-212029-11-201,147This jurisdiction approved 2025-08-29.
University of Montana - Helena School of TechnologyCollege/UniversityExpired on 2013-02-21University of Montana – Helena College of Technology Airport Campus Disaster Resistant University Multi-Hazard Mitigation Plan (FEMA plan 32491)2008-02-212013-02-21-4,969

Plan 110263 covers 53 other participants, named in the Excel file.

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

What the packet contains

Sections in FEMA checklist order; each heading names the review item its tables support. Full tables are in the downloads above.

Supports FEMA checklist item B1-a Hazard identification

14 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, tsunami and volcanic activity. That is the evidence for leaving them out of the plan.

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

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 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: 3 in hail, 1997-06-06; same size also recorded on 1975-07-01, 1982-06-28
  • Thunderstorm Wind: 76 kt (87 mph) measured gust, Thunderstorm Wind, 2010-06-29
  • Tornado: F0 tornado, 1997-06-27, 0.1 mi within this county, 10 yd wide, $2,000 property; crops not reported (1997 dollars)

Supports FEMA checklist item B1-d Previous occurrences

Federal declarations for this area: 16 declarations covering 12 separate hazard incidents counted in this packet; each with type, dates and county Public Assistance dollars.

New since the last plan (approved 2024-11-21): none.

3 statewide declarations listed separately.

Hazards with no Storm Events record and no federal declaration are stated as such (7 of 18).

Storm Events history: 1,159 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: Cold Wave, Hail, Inland Flooding, Strong Wind and Wildfire
  • Possible: Avalanche, Ice Storm and Tornado
  • Unlikely: Earthquake

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 15 of the 18 hazards (17 tracts; rated tracts only).

3 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 2024-11-21: $12,000 in county-coded records (11 records); $0 reported for the zone (75 zone records). 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 70,922; building value $15,540,261,931 and agriculture value $55,603,848 (total, not at risk).

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

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: 5 and 0.

Mitigated 0; insured 3; NFIP data as of 2026-08-02. Counts by occupancy group and for each jurisdiction are in the packet.

Releases

Each release is dated; this is release 2026-10. It was first published 2026-09-30; its files do not change except for dated corrections listed on the changelog (corrected 2026-10-01). Later releases will be listed here with what changed between them. All releases.

Cite this

Hazard Plain (2026). Lewis and Clark County, MT: risk-assessment baseline packet, release 2026-10 (data as of 2026-09-30; County FIPS 30049). Automated baseline. https://hazardplain.org/mt/30049/ Built from FEMA OpenFEMA, the FEMA National Risk Index and NOAA NCEI Storm Events; source versions in the packet's Sources list.

Source citations for the plan's bibliography (8)

How this packet is built: methods and sources