Clark County

Every recorded tornado

1. Injuries and deaths are for the tornado’s whole path, which may extend beyond the county. Deaths recorded within Clark 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.

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 (21).

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. Mar 13, 2018Flood$680,000
   National Weather Service narrative

   Snow melt began in earnest with warmer temperatures combined with periods of heavy rain in the latter half of March. This caused extensive sheet flooding in Clark County to the extent that the governor declared it a state of Idaho disaster area. Several county roads received extensive damage and were washed away. 1 home in the Medicine Lodge area flooded completely along with hay bail damage and crop damage. The Birch Creek Campground also had extensive damage with several campgrounds along the birch Creek washed away. The county placed damage estimates close to 700 thousand dollars.

2. Jan 7, 2022Winter Storm, Centennial Mountains-Island Park$100,000
   National Weather Service narrative

   Whiteout conditions caused by 40 plus mph wind gusts created a 40 vehicle crash on US Highway 20 in the east bound lane on January 7th. It initially occurred when a semi crashed into a stopped vehicle that was stopped due to the low visibility. Ambulances were involved in the pile up. The location was in the Henry's Lake flats in between Idaho Highway 87 and Island Park. Two police deputies were struck as well. Only very minor injuries were reported in the pile up with no deaths. The crash occurred at around 3 pm MST and US Highway 20 was closed for several hours as well as Idaho Highway 87 from Island Park to the Montana state line for several hours. Both were re-opened on the…

3. Feb 5, 2017Flood$67,000
   National Weather Service narrative

   Some minor flooding and road damage occurred from a combination of snow melt with the extensive warmup during the month.

4. Nov 27, 2022Winter Storm, Centennial Mountains-Island Park$25,000
   National Weather Service narrative

   Snow combined with wind gusts over 40 mph caused US Highway 20 to close on the 27th from Ashton to Targhee Pass as well as Idaho Highway 87 between US Highway 20 and Raynolds Pass. Many automobile accidents and slide offs were reported on US 20. Seven to 8 crashes were reported on US 20. Both highways closed at around 5 PM MST on the 27th. Snow amounts were in the 3 to 6 inch range in Island Park with 10 inches estimated at the White Elephant SNOTEL site. Wind gusts were widespread in the 35 to 45 mph range. Roads were reopened at 3 AM MST Monday the 28th.

5. Aug 7, 2003Wildfire$25,000
   National Weather Service narrative

   38,000 acre Deep fire northwest of Dubois in short grass, sagebrush and pockets of timber. Destroyed one outbuilding and cost 1.4 million dollars to suppress. Fire contained by August 11th.

6. Dec 23, 2023Winter Weather, Centennial Mountains-Island Park$20,000
   National Weather Service narrative

   Two to 4 inches of snow fell and combined with strong winds to create hazardous travel. Rocky Mountain Power reported 400 customers without power by 530 AM due to the winds and snow in the Ashton area and north. A jackknifed semi trailer occurred on US Highway 20 just north of Idaho Highway 87 blocking the road at 909 AM. Fremont County reported numerous crashes and slide offs in the Island Park area.

7. Apr 12, 2023Winter Weather, Centennial Mountains-Island Park$15,000
   National Weather Service narrative

   A winter and spring of heavy snow led to snow weight collapsing 3 structures including a garage near Ashton, a farm shed near Ashton and a canopy covering a fuel filling station at Mack's Inn in Island Park. Damages were 30,000 dollars.

8. Apr 16, 2026Winter Weather, Centennial Mountains-Island Park$10,000
   National Weather Service narrative

   Multiple car crashes occurred around 7:40 a.m on U.S. Highway 20 between mileposts 378 and 380 at the Osborne Bridge, which blocked all lanes from Bull Moose Lane to Henry���s Fork.|Fremont County Chief Deputy reported there was a single-car rollover that triggered a secondary two-car T-bone crash directly behind. Three people suffered injuries and were transported to the hospital. ||Around 4 inches of snow fell in the Island Park area.

9. Apr 15, 2019Winter Weather, Centennial Mountains-Island Park$10,000
   National Weather Service narrative

   Snow fell in Fremont County during the morning of the 15th with 2 to 4 inches. The snow caused very dangerous road conditions. A semi truck rolled off US Highway 20 near Elk Creek Station around milepost 388. Other crashes occurred north of Ashton and near Mack's Inn between 8 and 9 am MDT.

10. Mar 1, 2017Flood$10,000
    National Weather Service narrative

    Minor sheet flooding from snow melt continued in March but effects were minimal and mainly limited to road damage and some field flooding.

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

103°FJul 13, 2002

All-time low

−31°FDec 22, 1990

Warmest night

73°FJul 6, 1985

Coldest day

−13°FDec 22, 1983

Wettest day

2.60 inJun 26, 1944

Snowiest day

12.0 in2 times, most recently May 25, 1980

Hottest year

1934mean 49.1°F

Coldest year

1929mean 38.4°F

Wettest year

199521.34 in

Driest year

19265.62 in

Snowiest season

113.1 in1951-52

Station Dubois Experiment Station (USC00102707), 5,450 ft elevation, 4.6 miles from the population centre. Daily records from 1925 to September 30, 2026; 98.9% 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 USC00102707.
• 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.