Slope County

Every recorded tornado

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

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 ND GS (1,191).

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. Jan 9, 1997Blizzard, Slope$1.5 million
   National Weather Service narrative

   The second blizzard in less than 1 week brought North Dakota to a virtual standstill. This blizzard didn't bring as much snow as the first storm, but the winds gusted from the northwest as high at 40 mph and they lasted for 3 days. Snowfall amounts from this storm varied from 1-2 inches in the southwest to 2-4 inches in the central. But the strong winds combined with this snow as well as the snow from the blizzard a few days earlier created widespread whiteout conditions that lasted for 3 days. There were numerous communities that halted mail delivery and cancelled school. In Emmons Co. every road was blocked by drifts, some as high as 18 feet. In McLean Co. there was a drift at…

2. Apr 4, 1997Blizzard, Slope$1.4 million
   National Weather Service narrative

   Warm weather the first three days of April lead much of North Dakota to believe that spring had arrived with temperatures in the 60s and 70s. Mother Nature had other plans. A very strong area of low pressure moved out of the Colorado area into the northern plains. Warm moist air ahead of the low collided with cold air coming down from Canada. The result was the worst blizzard of the season for North Dakota, bringing much of the state to a complete halt. The precipitation began to fall during the afternoon of the 4th (Friday), as rain in the east and freezing rain or sleet in the west. By Friday evening the freezing rain and sleet had changed over to all snow in the west. By…

3. Jul 16, 2011Excessive Heat, Slope$700,000
   National Weather Service narrative

   Upper level high pressure centered over the Central Plains, coupled with persistent low pressure over the Rockies, brought a prolonged period of above seasonal temperatures and high humidity to west and central North Dakota. Daytime temperatures in the 90s combined with the high humidity to produce heat index values well over 100 degrees for many locations for several days. Heat index values topped out between 110 and 120 degrees, not a common thing in North Dakota.||Although no human life was lost and no injuries were reported, there were livestock losses associated with the heat. It is estimated that up to 700 head of cattle died from the heat wave. Estimated at near 1,000…

4. Jan 24, 2010Blizzard, Slope$588,000
   National Weather Service narrative

   Wind gusts to near 50 mph combined with falling snow and existing loose snow cover to create widespread blizzard conditions across Slope County. The strong winds and blizzard conditions resulted in additional downed power lines and delayed the repair of existing downed power lines. The total estimated damage from this storm (January 18th through January 25th) was 588,000 dollars.

5. Jul 20, 2017Thunderstorm Wind$400,000
   National Weather Service narrative

   A hopper style grain bin was destroyed at a ranch. Electrical poles in the area were snapped.

6. Apr 19, 2006Blizzard, Slope$250,000
   National Weather Service narrative

   See StormData entry for Winter Storm for Bowman and Slope counties for April 18 into 19, 2006. The winter storm intensified to a full scale blizzard with zero visibility in snow and blowing snow. Wind speeds were gusting from 35 to 45 mph at the height of the storm. Snow totals had a wide range over short distances. Totals were from 6 inches at Scranton to 22 inches at Bowman and 28 inches at Marmarth. Schools were closed. Power poles were downed under the weight of the heavy wet snow and about 500 people were without power at one time or another. No travel was advised throughout the counties as the storm brought major disruption to tranportation, commerce, and electrical service.…

7. Jan 4, 1997Blizzard, Slope$250,000
   National Weather Service narrative

   The first blizzard of 1997 hit east-central North Dakota on the morning of the 4th. The blizzard was preceeded by freezing rain that lasted most of the day before switching over to snow. The snow became so heavy that the highway department pulled the plows off of the roads the evening of the 4th and all day on the 5th. It was during the evening of the 4th that the northwest winds began to blow. Winds of 25 to 35 mph were common. Some of the higher snow amounts include 14 inches of snow at Ellendale (Dickey Co) and Linton(Emmons Co), 11 inches at Hague(Emmons Co) and 18 inches of snow at Oakes(Dickey Co). The roof collapsed at the Lull plant in Oakes from the weight of the snow.…

8. Jul 10, 2016Hail$150,000
   National Weather Service narrative

   Crops and vehicles were extensively damaged from the baseball sized hail.

9. Jul 10, 2016Hail$125,000
   National Weather Service narrative

   The ground was covered with golf ball sized hail. The hail dented frames on windows and broke window screens. Windshields were broken on vehicles.

10. Apr 30, 2011Blizzard, Slope$100,000
    National Weather Service narrative

    An estimated six to eight inches of heavy wet snow combined with winds gusting to around 65 mph to result in widespread blizzard conditions. Travel was impossible due to many roads blocked by snow.

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

112°FJul 6, 1936

All-time low

−43°F3 times, most recently Feb 16, 1936

Warmest night

85°FJul 23, 1921

Coldest day

−26°FFeb 1, 1917

Wettest day

5.40 inJul 13, 1966

Snowiest day

18.5 inApr 19, 2006

Hottest year

2012mean 46.3°F

Coldest year

1916mean 38.1°F

Wettest year

201333.21 in

Driest year

19195.87 in

Snowiest season

107.1 in1993-94

Station Bowman (USC00320995), 2,983 ft elevation, 15.7 miles from the population centre. Daily records from 1915 to October 27, 2026; 98.6% 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 USC00320995.
• 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.