Oliver County, North Dakota
Natural disaster risk, federal disaster history and flood insurance facts.
Oliver County, North Dakota has a very low overall risk from natural hazards in FEMA's National Risk Index. Its risk score is lower than 98% of US counties. It ranks 49th of 53 counties in North Dakota. The costliest hazards here are inland flooding, cold waves and hail. FEMA estimates about $2.6 million a year in expected losses, or roughly $1,382 per resident. Since 1966 it has been included in 20 federal disaster or emergency declarations for natural events (18 major disasters). The most recent was in September 2026 (severe storms, straight-line winds and tornadoes). Only 5 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 Oliver County
- 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.
- Insulate pipes in outside walls, crawl spaces and garages.
- Know how to shut off the main water valve.
- Ask about the roof age and any impact-rated shingles.
- Check your home policy for a separate wind and hail deductible.
All 18 hazards
What the ratings mean ›| Hazard | Rating | Score | Expected loss a year | |
|---|---|---|---|---|
| Inland flooding | 6.5 | $1M | ||
| Cold wave | 25.5 | $508K | ||
| Hail | 39.7 | $266K | ||
| Tornado | 11.7 | $134K | ||
| Winter weather | 41.3 | $72K | ||
| Strong wind | 6.2 | $64K | ||
| Ice storm | 32.5 | $56K | ||
| Wildfire | 44.5 | $51K | ||
| Heat wave | 5.3 | $9K | ||
| Lightning | 0.8 | $6K | ||
| Drought | 19.0 | $5K | ||
| Earthquake | 0.4 | $693 | ||
| Landslide | 6.6 | $19 |
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 low and community resilience is relatively high in FEMA's measures.
Federal disaster history
Recent disasters nationwide ›Declarations by decade
Federal declarations for natural events that included Oliver County. 2020s bar runs to November 2026.
By type
Most recent
Show all 20
North Dakota also had 25 statewide declarations that did not name single counties.
Storm history since 1974
Tornado risk by county ›The National Weather Service has logged 183 storm reports in Oliver County since 1974, with 0 deaths and 1 injury and about $2.2 million in reported damage. The strongest on record here was an F2 tornado on June 18, 1990.
Strongest tornadoes
| Date | Strength | Near | Hurt / killed |
|---|---|---|---|
| Jun 18, 1990 | F2 | – | 1 / 0 |
| Jul 7, 2020 | EF1 | Sanger | 0 / 0 |
| Jun 13, 1999 | F1 | Hannover | 0 / 0 |
| Nov 1, 2000 | F1 | Center | 0 / 0 |
| May 30, 1996 | F0 | Mandan | 0 / 0 |
Most damaging storms
| Date | Type | Near | Damage |
|---|---|---|---|
| Jun 2, 2011 | Flood | Ft Clark | $500K |
| Sep 4, 2014 | Hail | Center | $300K |
| Jun 18, 1990 | Tornado | – | $250K |
| Aug 11, 1993 | Thunderstorm Wind | Hannover | $100K |
| Jul 21, 2014 | Thunderstorm Wind | Center | $100K |
| Jun 27, 2025 | Hail | Hannover | $100K |
Source: NOAA Storm Events Database, county-based reports through Jun 7, 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 Oliver County
Check your address flood zone ›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 Oliver County
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; 893 housing units.
Compare in North Dakota
All 53 ›| Largest counties | Overall risk | Top hazard |
|---|---|---|
| Cass County | Inland flooding | |
| Burleigh County | Inland flooding | |
| Grand Forks County | Inland flooding | |
| Ward County | Cold wave | |
| Williams County | Cold wave | |
| Stark County | Cold wave | |
| Morton County | Inland flooding | |
| Stutsman County | Cold wave |
Neighboring counties
| County | Overall risk | Declarations |
|---|---|---|
| Burleigh County | 20 | |
| Morton County | 25 | |
| McLean County | 23 | |
| Mercer County | 23 |
Common questions about Oliver County
What is the biggest natural hazard in Oliver County?
Inland flooding has the highest expected yearly losses in Oliver County, about $1.4 million a year in FEMA's estimate. Cold wave is second at $508,446.
How many federal disasters has Oliver County had?
Oliver County has been included in 20 federal disaster or emergency declarations for natural events since 1966, including 18 major disasters. The most recent was Severe Storms, Straight-Line Winds, and Tornadoes in September 2026.
Is Oliver County a high-risk place to live?
Its overall rating is Very Low, 49th 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 Oliver County?
Standard home insurance does not cover flooding. About 1 in 167 homes in Oliver 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 Oliver County had?
NOAA records list 10 tornadoes in Oliver County since 1950. The strongest was an F2 tornado on June 18, 1990. The weather service has also logged 109 hail reports and 10 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.