Sioux County

Every recorded tornado

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

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 ND GS (710).

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. Apr 2, 2010Winter Storm, Sioux$7.0 million
   National Weather Service narrative

   Up to eight inches of heavy wet snow and sleet fell across Sioux County. The combination of strong winds and the wet snow resulted in widespread damages to electrical utilities, causing massive power outages across the county. In some areas it took several days to restore power. Preliminary damage assessments estimated there was around seven million dollars in damage from this storm for Sioux County.

2. Jan 25, 2010Blizzard, Sioux$1.8 million
   National Weather Service narrative

   Wind gusts up to near 50 mph combined with falling snow and existing loose snow cover to create widespread blizzard conditions across Sioux 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 well over one million dollars.

3. Jan 9, 1997Blizzard, Sioux$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…

4. Jul 13, 2010Hail$1.5 million
   National Weather Service narrative

   A North Dakota state record tying hailstone of five inches in diameter fell at Prairie Knights Casino and Resort. The resort, and all vehicles outside, sustained severe damage from the extreme hail. One of these large hail stones crashed through the windshield of a car, injuring the two occupants. This tied the record size five inch diameter hailstone in Mercer County on August 3, 1969.

5. Apr 4, 1997Blizzard, Sioux$1.3 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…

6. May 16, 1996Thunderstorm Wind$850,000
   National Weather Service narrative

   As the Bow Echo moved through the town of Cannonball, 6-7 mobile homes sustained damage...with 4 of the homes completely destroyed. The local electric company reported that many of the power poles that were in the area were snapped off or heavily leaning. Wind speed and property damage estimated.

7. Jul 8, 2019Flash Flood$750,000
   National Weather Service narrative

   Flash flooding resulted in a section of BIA Road 3, locally known as the Kenel Road which connects with ND Highway 1806, being washed out at the crossing with Joe Bush Creek. The culvert washed out and the road collapsed. Four vehicles drove into the washout and resulted in two fatalities and two injuries.

8. Oct 11, 2015Wildfire, Sioux$750,000
   National Weather Service narrative

   A grass fire that burned approximately 5,000 acres in Sioux County destroyed three homes, a church, and another structure in the Cannon Ball area. The Cannon Ball Elementary School was damaged from smoke and ash, and playground equipment was destroyed. The 550 residents of Cannon Ball were evacuated, and 54 families were sheltered overnight at Prairie Knights Lodge. Winds were sustained at 40 mph with gusts to 60 mph.

9. Jul 13, 2010Hail$750,000
   National Weather Service narrative

   This was the first of three waves of very large hail to impact the city of Cannon Ball during this episode. Severe damage to vehicles, homes, and crops occurred.

10. Mar 6, 2009Flood$264,000
    National Weather Service narrative

    Cedar Creek and the Cannonball River flooded. Overland flooding damaged state, county and township roads. Two homes were flooded. Flooding continued into April.

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

118°FJul 20, 1934

All-time low

−51°FFeb 16, 1936

Warmest night

81°F3 times, most recently Jul 10, 1936

Coldest day

−25°FJan 12, 1912

Wettest day

5.10 inJun 30, 1909

Snowiest day

15.0 inFeb 26, 2009

Hottest year

1987mean 48.4°F

Coldest year

1951mean 37.8°F

Wettest year

201928.16 in

Driest year

19363.66 in

Snowiest season

89.5 in2018-19

Station Pollock (USC00396712), 1,639 ft elevation, 27.9 miles from the population centre. Daily records from 1908 to October 22, 2026; 98.7% 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 USC00396712.
• 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.