Grand County

Every recorded tornado

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

Claims by ZIP code

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.

Mapped landslides

Mapped by UT GRC (337), NASA (3).

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. Oct 2, 2022Flash Flood$26.0 million
   National Weather Service narrative

   More than 50 people were stranded overnight in Grand County, Utah after heavy rain from severe thunderstorms wiped out a portion of Mineral Bottom Road which led to a remote boat ramp. The rain completed demolished a section of switchbacks with large boulders accumulating.

2. Aug 20, 2022Flash Flood$9.5 million
   National Weather Service narrative

   Training thunderstorms produced upwards of 1 to 2 inches of rain within one to two hours in an around Moab. The Mill Creek Parkway - a recreational path that runs through the center of Moab, was reported to be ���completely decimated��� as a result of the flooding. Several areas had their water turned off after flood waters led to a broken water main. Numerous homes and businesses had upwards of 12 inches of water and debris inside resulting in significant property damage.

3. Aug 19, 2010Flash Flood$2.5 million
   National Weather Service narrative

   Heavy rainfall within a short period of time resulted in flash flooding across the heavily used Mineral Bottom Road. Mineral Bottom Road was deeply washed out in the switchback section and an extensive amount of debris covered the road, which remained impassable as of mid September 2010. The road washout stranded 29 people who were airlifted by helicopter. The KGJX WSR-88D radar estimated 1.86 inches of rain within 60 minutes in the source region of the Mineral Bottom Road flash flood. The NPS' Island-In-The-Sky visitors center personnel measured 1.05 inches of rain, most of which fell within a half hour. Other locations in the area likely received flash flooding.

4. Jul 28, 2021Flash Flood$2.5 million
   National Weather Service narrative

   Heavy rain led to flash flooding in downtown Moab.

5. Aug 5, 2017Flash Flood$1.0 million
   National Weather Service narrative

   Heavy rainfall resulted in a flash flood which flowed down drainages that funneled downstream to Westwater and into the Colorado River. The flash flood negatively impacted 6 gas production wells and washed away several pipelines and tanks. An estimated 275 million cubic feet of natural gas was lost. Most of the equipment was found several miles downstream.

6. Oct 6, 2006Flood$500,000
   National Weather Service narrative

   Persistent moderate to heavy rainfall resulted in widespread flooding and flash flooding across much of east central Utah, including Arches National Park. One park ranger said it was the worst flooding she had seen in Arches in 14 years. In the Park, Courthouse Wash ran 12 to 14 feet deep. Roads were closed and washed out in some areas, while some trails were obliterated. The trailhead of Delicate Arch was impassable as flood waters from Salt Wash created a 50 to 60 foot wide channel, blocking pedestrian access. On the evening of Friday, October 6, park employees and Grand County Search And Rescue volunteers ferried 20 adults and 4 children to safety after raging waters in Salt…

7. Jul 13, 2021Flash Flood$500,000
   National Weather Service narrative

   An NWS storm survey found evidence of a major flash flooding event in the Westwater Drainage Valley. Water was estimated to be 6 to up to 12 feet deep based on erosion of the arroyo walls. Numerous instances of dry arroyo crossings were washed out with significant transport of sediment and debris downvalley.

8. Aug 20, 2022Flash Flood$250,000
   National Weather Service narrative

   Areas along Mill Creek experienced flash flooding as the creek overflowed due to heavy rain from thunderstorms. Water flowed over a park bridge, a dam had damage as an 18 inch diversion pipe cracked and filled with sand, and debris backed up on culverts which resulted in significant overland flooding.

9. Aug 20, 2022Flash Flood$250,000
   National Weather Service narrative

   Debris from Mill Creek flowed into the Colorado River as a result of heavy rain from thunderstorms.

10. Sep 6, 1997Flash Flood$175,000
    National Weather Service narrative

    Up to 1.50 inches of rain fell within a half hour in the Moab area, with flood waters up to 5 feet deep in some areas. A private dam overflowed. Many basements were flooded, and some driveways and roads were washed out or damaged.

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

116°FJul 13, 2003

All-time low

−8°F2 times, most recently Feb 7, 1989

Warmest night

87°FJul 13, 2026

Coldest day

11°FFeb 6, 1989

Wettest day

1.62 inSep 8, 2002

Snowiest day

6.0 in3 times, most recently Dec 4, 2013

Hottest year

2018mean 60.2°F

Coldest year

1991mean 55.1°F

Wettest year

200613.41 in

Driest year

20123.87 in

Snowiest season

22.3 in1988-89

Station Arches Np Hqs (USC00420336), 4,093 ft elevation, 5.9 miles from the population centre. Daily records from 1980 to October 20, 2026; 93.1% 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 USC00420336.
• 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.
• 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.