Enter any address in Lemhi County, Idaho to see its FEMA flood zone
Flash flooding from thunderstorms and ice jam related flooding on rivers are the dominant flood types in Lemhi County. Recent events include ice jam flooding in January 2023, caused by significant cold temperatures and ice buildup on the Lemhi River. In June 2023, anomalous atmospheric moisture triggered debris flows from slow-moving thunderstorms.
Homeowners in Lemhi County should be aware of flood risks, particularly those in Zone A, which has seen the highest number of National Flood Insurance Program claims and the deepest average water depths. Properties located near rivers and streams, or in areas prone to flash flooding from heavy rainfall and debris flows, should also pay close attention to flood risk.
Summary generated from NOAA storm narratives and NFIP claim data for this county. Not predictive.
9 NOAA storm reports from this county describe what happened, in the words of the meteorologists who were there.
Lemhi County, Idaho has recorded 26 flood-related events since 1996 according to NOAA's Storm Events Database, including 16 flash floods and 10 river or area floods. The county has received 5 federal disaster declarations. Enter any address above to check its FEMA flood zone designation.
FEMA Disaster Declarations (1984–2020)
Source: OpenFEMA Disaster Declarations Summaries.
| Declaration | Type | Date |
|---|---|---|
| Covid-19 | Biological | Jan 20, 2020 |
| Covid-19 Pandemic | Biological | Jan 20, 2020 |
| Hurricane Katrina | Hurricane | Aug 29, 2005 |
| Wildfires | Fire | Jul 27, 2000 |
| Ice Jams And Flooding | Snowstorm | Jan 17, 1984 |
NOAA Storm Events Database (1996–2025)
Source: NOAA National Weather Service Storm Events Database.
| Type | Date | Damage |
|---|---|---|
| Flash Flood | Jun 30, 2024 | 250.00K |
| Flood | Jan 29, 2023 | 0.00K |
| Flash Flood | Jun 6, 2023 | 0.00K |
| Flash Flood | Aug 10, 2019 | 0.00K |
| Flood | May 31, 2017 | 0.00K |
| Flood | May 7, 2017 | 0.00K |
| Flood | Jun 1, 2017 | 10.00K |
| Flood | Feb 6, 2015 | 40.00K |
| Flash Flood | Aug 13, 2014 | 0.50K |
| Flash Flood | Jun 29, 2013 | 5.00K |
Flash Flood — Jun 30, 2024
Flooding occurred along the Salmon River Road as brief but intense rainfall occurred.
Flood — Jan 29, 2023
Winter temperatures were the in the top 5 for coldest resulting in significant ice buildup on the Lemhi River. Cold temperatures culminated on January 30th with a low of -33F in Leadore and -18F in Salmon. Ice jam related flooding occurred around this significant cold period.
Flash Flood — Jun 6, 2023
Anomalous atmospheric moisture with slow moving thunderstorms triggered a few debris flows in Lemhi County.
Flash Flood — Aug 10, 2019
An evening severe thunderstorm brought damaging hail and flash flooding along Highway 95 in central Idaho. Another storm brought quarter-sized hail and a debris flow north of Salmon.
Flood — May 31, 2017
Warmer than normal temperatures causes rapid snow melt and leads to a prolonged period of flooding on the Salmon River. The Salmon river continued to rise into the month of June where the greatest impacts occurred. Only minor flooding was observed during the month of May. See the month of June for more detailed information.
Source: NOAA National Weather Service Storm Events Database.
Source: OpenFEMA NFIP Individual Claims (2.25M records analyzed).
FEMA assigns flood zone designations to areas in Lemhi County, Idaho:
AE High Risk — 1% annual chance of flooding. Insurance required.
VE Very High Risk — Coastal flooding with wave action.
X (Shaded) Moderate Risk — 500-year floodplain.
X Low Risk — Outside major floodplains.
Properties in Lemhi County, Idaho that are in FEMA-designated Special Flood Hazard Areas (zones A and V) with federally backed mortgages are required to carry flood insurance.
Even outside high-risk zones, flood insurance is recommended. From 2014 to 2024, nearly one-third of NFIP claims came from outside the high-risk Special Flood Hazard Area.
Visit FloodSmart.gov to find an agent and get a quote.