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Sioux County, North Dakota

Natural disaster risk, federal disaster history and flood insurance facts.

Relatively Low overall risk
4th of 53highest risk in North Dakota
$12Mexpected losses a year
20federal declarations
1 in 333homes with flood insurance
Photo: Bold Frontiers, CC BY 2.0

Sioux County, North Dakota has a relatively low overall risk from natural hazards in FEMA's National Risk Index. Its risk score is higher than 62% of US counties. It ranks 4th of 53 counties in North Dakota. The costliest hazards here are cold waves, inland flooding and strong wind. FEMA estimates about $12 million a year in expected losses, or roughly $3,203 per resident. Since 1969 it has been included in 20 federal disaster or emergency declarations for natural events (16 major disasters). The most recent was in September 2025 (severe storm, tornadoes and straight-line winds). Only 3 homes here carry federal flood insurance.

FEMA National Risk Index December 2025; OpenFEMA declarations to Nov 6, 2026; NFIP records. Updated November 6, 2026.

Top risks in Sioux County

$10.2 million a yearExpected losses. Damaging events about 13 times a year.
  • Insulate pipes in outside walls, crawl spaces and garages.
  • Know how to shut off the main water valve.
$726,274 a yearExpected losses. Damaging events about once every 2 years.
  • Check the FEMA flood map for your address, and ask the seller or landlord about past flooding.
  • Price a flood policy now. Most new federal policies take 30 days to start.

Strong wind

Moderate
$435,889 a yearExpected losses. Damaging events about 2 times a year.
  • Secure outdoor furniture and trash bins before storms.
  • Have trees near the house checked.
HazardRatingScoreExpected loss a year
Cold waveHigh97.6
$10M
Inland floodingVery Low10.0
$726K
Strong windModerate62.9
$436K
HailModerate77.4
$422K
WildfireLow80.5
$236K
TornadoVery Low25.0
$201K
Winter weatherModerate81.0
$123K
Ice stormLow46.8
$41K
LightningVery Low19.7
$37K
Heat waveVery Low16.3
$24K
DroughtVery Low24.0
$5K
EarthquakeVery Low5.4
$3K
LandslideVery Low17.2
$45

Scores are percentiles: a score of 90 means higher risk than about 90% of US counties for that hazard. Hazards FEMA does not rate here are left out. Social vulnerability is very high and community resilience is very low in FEMA's measures.

Federal disaster history

Recent disasters nationwide ›

Declarations by decade

Federal declarations for natural events that included Sioux County. 2020s bar runs to November 2026.

By type

Severe Storm9
Flood8
Snowstorm1
Fire1
Coastal Storm1

Most recent

Sep 11, 2025Severe Storm, Tornadoes, and Straight-Line WindsMajor disaster
Sep 1, 2021Severe Storm, Straight-Line Winds, and FloodingMajor disaster
Oct 31, 2013Severe Winter StormMajor disaster
May 10, 2011FloodingMajor disaster
Apr 7, 2011FloodingEmergency
Apr 21, 2010Severe Winter StormMajor disaster
Feb 26, 2010Severe Winter StormMajor disaster
Mar 24, 2009Severe Storms and FloodingMajor disaster
Sep 13, 2005Hurricane Katrina EvacuationEmergency
Jul 22, 2005Severe Storms, Flooding, and Ground SaturationMajor disaster
Show all 20
Jun 29, 2002Nd - Again Fire - 06/29/2002Fire management
Jun 8, 1999Severe Storms, Flooding, Snow, Ice, Ground Saturation, Lanslides, Mudslides, and TorMajor disaster
Apr 7, 1997Severe Flooding,Severe Winter Storms, Snowmelt, Spring RainsMajor disaster
Jan 12, 1997Severe Winter Storms and Blizzard ConditionsMajor disaster
May 16, 1995Severe Storms, Flooding, and Ground SaturationMajor disaster
Jul 26, 1993Severe Storms & FloodingMajor disaster
Apr 17, 1978Storms, Ice Jams, Snowmelt & FloodingMajor disaster
Feb 16, 1978Blizzard & SnowstormsEmergency
May 24, 1975Flooding From Rains & SnowmeltMajor disaster
Apr 18, 1969FloodingMajor disaster

North Dakota also had 25 statewide declarations that did not name single counties.

Storm history since 1956

Tornado risk by county ›

The National Weather Service has logged 205 storm reports in Sioux County since 1956, with 2 deaths and 8 injuries and about $8.1 million in reported damage. The strongest on record here was an EF1 tornado on May 24, 2010 near Selfridge.

17tornadoes
114hail reports, largest 5 inches
60damaging thunderstorm winds
13floods and flash floods

Strongest tornadoes

DateStrengthNearHurt / killed
May 24, 2010EF1Selfridge0 / 0
Aug 28, 2024EF1Selfridge0 / 0
Jun 21, 1983F1–0 / 0
Jun 25, 1999F1Selfridge0 / 0
Jun 28, 1996F0Ft Yates0 / 0

Most damaging storms

DateTypeNearDamage
Jul 13, 2010HailCannon Ball$2M
Jul 13, 2010HailCannon Ball$1M
May 16, 1996Thunderstorm WindCannonball$850K
Jul 8, 2019Flash FloodFt Yates$750K
Jul 4, 1994HailLemmon Sd$550K
Jul 14, 2010HailSolen$500K

Source: NOAA Storm Events Database, county-based reports through Jul 3, 2026. Tornado records start in 1950, hail and wind in 1955, and floods and other storm types in 1996, so older decades undercount. Damage is in dollars of the year it happened and is often an estimate. Winter storms, heat and hurricanes are logged by forecast zone, not county, so they are not counted here.

Flood insurance in Sioux County

Check your address flood zone ›
0.3%of homes have federal flood insurance (3 policies)
0%of homes in mapped high-risk flood zones are insured
$374paid on 2 flood claims since 1978
1978costliest year, with $374 paid

National Flood Insurance Program (NFIP) records only; private flood policies are not included. Home counts as of Aug 3, 2026. Since 2021 NFIP prices each home separately under Risk Rating 2.0, so your price depends on the building, not the county. Ask an agent for a quote.

Homes in Sioux County

$85,400median home value (North Dakota $249,900, US $332,700)
1984median year homes were built (North Dakota 1982, US 1980)
44%of homes built before 1980, before many modern wind, quake and flood building rules
12%of homes are mobile homes, which are the least safe in tornadoes and high winds

Older homes and mobile homes usually suffer more damage in storms, floods and earthquakes, and can cost more to insure. If you are buying, ask about roof age, foundation bolting and any retrofits. Source: US Census Bureau, American Community Survey 2020 to 2024 5-year estimates; 1,280 housing units.

Compare in North Dakota

All 53 ›
Largest countiesOverall riskTop hazard
Cass CountyModerateInland flooding
Burleigh CountyModerateInland flooding
Grand Forks CountyLowInland flooding
Ward CountyLowCold wave
Williams CountyLowCold wave
Stark CountyVery LowCold wave
Morton CountyLowInland flooding
Stutsman CountyLowCold wave

Neighboring counties

CountyOverall riskDeclarations
Morton CountyLow25
Corson County, SDVery Low14
Emmons CountyLow24
Grant CountyVery Low25
Adams CountyVery Low13

Common questions about Sioux County

What is the biggest natural hazard in Sioux County?

Cold wave has the highest expected yearly losses in Sioux County, about $10.2 million a year in FEMA's estimate. Inland flooding is second at $726,274.

How many federal disasters has Sioux County had?

Sioux County has been included in 20 federal disaster or emergency declarations for natural events since 1969, including 16 major disasters. The most recent was Severe Storm, Tornadoes, and Straight-Line Winds in September 2025.

Is Sioux County a high-risk place to live?

Its overall rating is Relatively Low, 4th highest of 53 in North Dakota. A county rating covers the whole area. Risk at one address can be much higher or lower, so check the FEMA flood map and ask about the home's history.

Do I need flood insurance in Sioux County?

Standard home insurance does not cover flooding. About 1 in 333 homes in Sioux County has federal flood insurance. Lenders require it in mapped high-risk zones, but many flood claims come from outside those zones.

How many tornadoes has Sioux County had?

NOAA records list 17 tornadoes in Sioux County since 1950. The strongest was an EF1 tornado on May 24, 2010 near Selfridge. The weather service has also logged 114 hail reports and 13 floods here.

Sources: FEMA National Risk Index (December 2025), OpenFEMA Disaster Declarations Summaries, and NFIP policy and claims data. Hazard Compass is independent and not affiliated with FEMA. These figures describe the whole county, not a single property, and are not insurance or safety advice. Report a problem.