Custer County

Every recorded tornado

1. Injuries and deaths are for the tornado’s whole path, which may extend beyond the county. Deaths recorded within Custer County: 0.
2. Weak tornadoes were under-recorded before Doppler radar coverage became national in the early 1990s, so earlier decades read low. Ratings use the Fujita scale before February 2007 and the Enhanced Fujita scale after.

Storm Prediction Center severe weather database, 1950 to 2025.

Every large fire

1. Large fires mapped by the Monitoring Trends in Burn Severity program since 1984: 1,000 acres or more in the West, 500 or more in the East. Prescribed burns are excluded. Acres here are the part of each perimeter inside this place.

Monitoring Trends in Burn Severity (USGS and U.S. Forest Service), 1984 to 2026.

Smoke overhead

1. A smoke day is a date on which a smoke plume traced by NOAA Hazard Mapping System analysts from satellite imagery covered this place's point (the county's population centre or the city centre). Counts here are of medium or heavy smoke. Since 2018 analysts have often drawn light smoke as one area over most of the continent, so light-smoke counts are not comparable from year to year. The plumes show smoke anywhere in the air above, not air quality at the ground, and smoke hidden by cloud is missed.

NOAA Hazard Mapping System smoke analysis, 2011 to 2026, retrieved October 30, 2026.

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).

OpenFEMA NFIP Redacted Claims v3, refreshed August 4, 2026. NOAA Storm Events through 2026.

River crests

River gauges

1. Crests are the highest and the recent crests the National Weather Service lists for each river gauge in the county that has a flood stage, not every flood. Flood categories use each gauge's current flood stages; crests from before levees, dams or channel changes may not be comparable. Crests measured on an old datum are left out of the rankings.

NOAA National Water Prediction Service gauge records, retrieved October 30, 2026.

1. The Palmer Drought Severity Index is computed by NOAA each month from the county's average temperature and precipitation, relative to the county's own climate. Zero is normal; -3 or lower is severe drought and -4 or lower extreme drought. It describes the long-term balance of moisture, not water supply or crop losses.

NOAA NCEI nClimDiv county Palmer Drought Severity Index, 1895 to September 2026, issued October 6, 2026.

Every earthquake of magnitude 4 or more within 50 miles

1. Earthquakes of magnitude 2.5 or more in the USGS Comprehensive Catalog since 1900. Within 50 miles means the epicentre lies within 50 miles of the county boundary (or inside the county).
2. Small earthquakes were under-recorded before the modern seismic networks of the 1970s and are still missed in remote areas, so early decades read low. Magnitudes are as the catalogue reports them and mix scales (moment, local and body-wave).

USGS ANSS Comprehensive Earthquake Catalog, 1900 to present, retrieved October 30, 2026.

Volcanoes within 100 miles

1. U.S. volcanoes within 100 miles, from the USGS Volcano Hazards Program. The threat category is the USGS 2018 National Volcanic Threat Assessment, which ranks volcanoes by how hazardous their past eruptions were and how many people and how much infrastructure lie near them. It is not a forecast of eruption.

USGS Volcano Hazards Program, retrieved October 30, 2026.

Mapped landslides

Mapped by ID GS (152), USGS Conterminous (9).

1. Landslides mapped in the USGS compilation of landslide inventories across the United States (version 3.0, 2025), rated probable or better. The compilation joins inventories made by federal and state agencies for different purposes and areas, so the number mapped in a county reflects how closely it has been surveyed as much as how often its slopes fail. An area with few records may simply not have been mapped. Deaths are as recorded in the inventories; a slide listed in two inventories is counted once.

USGS Landslide Inventories across the United States, version 3.0, retrieved October 27, 2026.

More event types since 1996

Costliest events since 1996

1. May 1, 2017Flood$3.5 million
   National Weather Service narrative

   The Salmon River in Salmon reached moderate flood stage in May and this caused flooding from the headwaters of the Salmon south through Challis into Custer County. Trail Creek, Valley Creek, Garden Creek and Antelope Creek all overflowed banks with flood warnings throughout the month continuing in Custer County. Major damage occurred to backcountry roads and campgrounds. Significant agriculture damage occurred due to flooded fields. Road and bridge damage required significant repair along with significant USFS infrastructure damage. The cost of damage and flood protection rose above 3 million dollars for the month.

2. Sep 1, 2024Wildfire, Sawtooth-Stanley Basin$2.0 million
   National Weather Service narrative

   The Wapiti fire began July 24th from lightning strikes near Grandjean in the Boise National Forest for eventually spread into the Sawtooth and Salmon Challis National Forests in the latter part of August and continued burning through September in the Sawthooths and Salmon Challis. Idaho State Highway 21 was closed from Stanley to Lowman in late August and remain closed unto September 18th. The Idaho Transportation Board approved 2 million dollars of highway repair for Highway 21 due to several miles of guardrail replacement as well as sign replacement and damaged pavement. The fire burned over 129,000 acres. Stanley schools were closed the first 7 days of classes in the 2024…

3. Oct 1, 2024Wildfire, Sawtooth-Stanley Basin$1.5 million
   National Weather Service narrative

   The wildfire near Stanley which burned all of September about 130,000 acres continued into October. Final damage estimates were about 1.2 million dollars in the city of Stanley and about 300,000 dollars for Redfish Lake Lodge due to loss of business for over a month.

4. Jun 1, 2017Flood$900,000
   National Weather Service narrative

   The Salmon River in Salmon had reached moderate flood stage in May and stayed at flood stage into June and this caused flooding from the headwaters of the Salmon south through Challis into Custer County. The Yankee Fork and East fork of the Salmon River flooded along with Thompson Creek, Squaw Creek, Kinnikinic Cerek and Bayhorse and Garden Creek. Most side tributaries recorded record flows. The Valley Creek in Stanley flooded with the peak flow on June 5th. The Big Lost River at Howell Ranch recorded its second highest peak ever and the Big Lost below Mackay Dam reached minor flood stage as well with peak flows continuing through the end of June. Homes, businesses, roads and…

5. Jul 3, 2008Thunderstorm Wind$420,000
   National Weather Service narrative

   Microburst winds estimated to be as high as 95 mph did extensive damage at the Redfish Lake campgrounds. Up to 1,000 Lodge-pole pine trees were uprooted with several snapped 3 to 5 feet above ground level. Twenty to forty Douglas Firs uprooted as well. The average diameter of the snapped Lodge-pole pine trees was 5 to 14 inches and the average Douglas Fir diameter was 10 to 24 inches. At the Glacier View Campground, 3 people camping were injured including one sustaining a broken leg. All of those injured were taken by ambulance to care facilities. Campground facilities were damaged with multiple vehicles damaged from the trees falling as well.

6. Apr 8, 2019Avalanche, Sun Valley Region$200,000
   National Weather Service narrative

   Multiple avalanches occurred near Ketchum on April 8th. The first one was around 2:30 PM and severely damaged two homes believed to be unoccupied on Warm Springs Road west of Ketchum. It was a large wet slab avalanche. The total assessed value of the damaged homes was approximately $200,000. A second avalanche in the same location occurred at around 6:45 PM but no houses, or vehicles were involved.

7. Feb 5, 2017Flood$195,000
   National Weather Service narrative

   The combination of record or near record snows in December and January with a warmup in February caused sheet flooding and some ice jam flooding as well. An ice jam on the Lost River near Darlington caused flooding to some homes on that river. Extensive road damage occurred throughout the county with the snow and snow melt combinations. And the warmup aided in weight on roofs and collapses in many cases throughout Custer County. The county declared a county disaster due to the damages.

8. Sep 1, 2022Wildfire, Sun Valley Region$100,000
   National Weather Service narrative

   The Ross Fark wildfire began in Camas County August 14th and spread into Blaine and Custer Counties in late August into early September. It was timber litter, timber and short grass that fueled the fire. By September 4th the fire expanded from 3 thousand acres to over 5 thousand acres. Blaine County Sherriff's office issued a mandatory evacuation notice on September 4th for the Sawtooth City, Smiley Creek, Lake Alturas, and the Beaver Creek areas in the Stanley Basin all cabins and campgrounds. State Highway 75 was shut down 5 miles south and north of Smiley Creek. A disaster declaration was declared on September 6th by Blaine County. The fire had grown to 14 thousand acres by…

9. Mar 1, 2017Flood$90,000
   National Weather Service narrative

   Road damage from melting of heavy winter snows continued throughout the county along with mainly minor field flooding and occasional ice jams near the Butte County border.

10. Jul 22, 2026Flash Flood$75,000
    National Weather Service narrative

    Flash flooding occurred with heavy rainfall on the 22nd over the Custer Motorway near Mill Creek. The Motorway was closed due to some rain caused mudslides causing some washouts.

1. Storm Events records before 1996 cover only tornadoes, thunderstorm wind and hail. Damage figures are as reported by the National Weather Service at the time, not adjusted for inflation.

NOAA NCEI Storm Events Database, 1950 to 2026, issued October 26, 2026.

All-time high

88°FJul 30, 2000

All-time low

−29°FDec 20, 1990

Warmest night

57°FJul 17, 2022

Coldest day

−15°FDec 20, 1990

Wettest day

2.30 inSep 4, 2026

Hottest year

2015mean 36.2°F

Coldest year

2011mean 32.4°F

Wettest year

201743.60 in

Driest year

198521.80 in

Station Mill Creek Summit (USS0014E01S), 8,800 ft elevation, 23.4 miles from the population centre. Daily records from 1989 to October 26, 2026; 99.7% of days in the last 30 years are complete. Records at a single station can differ from a city’s official threaded record, which may combine several stations.

NOAA NCEI Global Historical Climatology Network Daily.

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).

OpenFEMA Disaster Declarations Summaries, retrieved October 30, 2026. Statewide declarations are not listed.

Neighbouring counties

• Tornadoes NOAA Storm Prediction Center severe weather database, through 2025.
• Tropical cyclones NOAA National Hurricane Center HURDAT2 (Atlantic; Northeast and Central Pacific), through 2025.
• Wildfire USGS/USFS Monitoring Trends in Burn Severity, through 2026.
• Storm events NOAA NCEI Storm Events Database, through 2026.
• Flood insurance OpenFEMA NFIP Redacted Claims v3, refreshed August 4, 2026.
• Declarations OpenFEMA Disaster Declarations Summaries v2, retrieved October 30, 2026.
• Weather records NOAA NCEI Global Historical Climatology Network Daily, station USS0014E01S.
• River crests NOAA National Weather Service, National Water Prediction Service river gauges, retrieved October 30, 2026.
• Drought NOAA NCEI nClimDiv county Palmer Drought Severity Index, through September 2026.
• Smoke NOAA NESDIS Hazard Mapping System smoke analysis, retrieved October 30, 2026.
• Volcanoes USGS Volcano Hazards Program, U.S. volcanoes and 2018 threat assessment.
• Landslides USGS Landslide Inventories across the United States, version 3.0 (2025).
• Earthquakes USGS ANSS Comprehensive Earthquake Catalog (ComCat), retrieved October 30, 2026.

Joins, thresholds and known limits are set out in the methodology. Found an error? Report it. Page built October 30, 2026.