Delaware County, Oklahoma: Natural Disaster Risk and History
Delaware County, Oklahoma has a Relatively Moderate natural-hazard risk rating in FEMA's National Risk Index (v1.20, December 2025): a score of 82.7 out of 100, higher than about 82% of US counties, with ice storms, heat waves and wildfires scoring highest of its 18 hazards and $30 million a year in expected losses.
OpenFEMA lists 31 federal disaster declarations that included Delaware County since 1973, not counting 2 for COVID-19; the latest is DR-4791-OK (Severe Storms, Straight-Line Winds, Tornadoes, and Flooding, declared 14 June 2024). NOAA's Storm Prediction Center recorded 64 tornadoes touching Delaware County from 1950 to 2025.
Live weather alerts for Oklahoma All official warnings Latest FEMA declarations
Population 40,338 Buildings worth $8.5 billion Area 800 sq mi Risk rank in Oklahoma 9 of 77 FIPS 40041
All 18 hazards, highest risk first
FEMA National Risk Index| Hazard | Risk rating | Score | Expected loss a year | How often | Events in record |
|---|---|---|---|---|---|
| Ice storm | Very High | 98.1 | $1.8 million | about 1.6 a year | 109 |
| Heat wave | Relatively Moderate | 92.0 | $2.2 million | about 17 a year | 252 |
| Wildfire | Relatively Moderate | 90.8 | $935,966 | about once every 137 years | — |
| Strong wind | Relatively High | 90.3 | $1.3 million | about 6.7 a year | 256 |
| Tornado | Relatively Moderate | 87.0 | $3.5 million | about once every 1.2 years | 57 |
| Inland flooding | Relatively Moderate | 86.5 | $17 million | about 1.4 a year | 39 |
| Winter weather | Relatively Moderate | 80.6 | $131,452 | about 1 a year | 195 |
| Landslide | Relatively Low | 75.2 | $5,633 | about once every 1.7 years | — |
| Cold wave | Relatively Moderate | 74.1 | $1.6 million | about 1.7 a year | 33 |
| Hail | Relatively Low | 72.5 | $381,889 | about 8.2 a year | 312 |
| Lightning | Relatively Moderate | 71.5 | $319,975 | about 56 a year | 132,026 strikes |
| Drought | Relatively Moderate | 64.1 | $227,620 | about 14 a year | 518 |
| Earthquake | Relatively Low | 60.5 | $282,095 | about once every 667 years | — |
| Hurricane | Very Low | 44.6 | $26,960 | about once every 136 years | 2 |
| Avalanche | Not Applicable | — | — | — | — |
| Coastal flooding | Not Applicable | — | — | — | — |
| Tsunami | Not Applicable | — | — | — | — |
| Volcanic activity | Not Applicable | — | — | — | — |
Score: FEMA's percentile among US counties that face the hazard (higher = more risk). Expected loss: FEMA's modelled average yearly loss to buildings, people (as a statistical value) and crops. How often: FEMA's annualised frequency of the hazard in the county; for some hazards it counts event-days, so it is a rough guide, not a forecast. "Not Applicable" means FEMA does not model that hazard here.
Federal disaster declarations 31
Most common: Severe Storm 18, Severe Ice Storm 7, Flood 3, Tornado 1.
| Decade | Declarations | Incident types |
|---|---|---|
| 1970s | 2 | Flood, Severe Storm |
| 1980s | 1 | Flood |
| 1990s | 1 | Severe Storm |
| 2000s | 12 | Severe Storm ×5, Severe Ice Storm ×4, Flood, Fire, Hurricane |
| 2010s | 11 | Severe Storm ×9, Tornado, Severe Ice Storm |
| 2020s | 4 | Severe Storm ×2, Severe Ice Storm ×2 |
The last 10
Widest declarations that included Delaware County
- Severe Winter Storms (2021, DR-4587-OK): 77 Oklahoma counties designated.
- Severe Winter Storm (2021, EM-3555-OK): 77 Oklahoma counties designated.
- Severe Winter Storm (2011, EM-3316-OK): 77 Oklahoma counties designated.
Named storms in its declarations: Hurricane Katrina (2005).
Not counted above: 2 COVID-19 ("Biological") declarations — in 2020 every US county was included. Oklahoma also had 24 statewide declarations with no county list.
Tornado record since 1950 64
| Tornadoes touching the county | 64 |
|---|---|
| Strongest-rated | (E)F3 ×5 |
| Peak month | May (34) |
| Deadliest | 22 May 2011, EF2, 2.9 mi path, 0 killed, 12 injured |
| Longest path | 29 Dec 1972, F2, 31.2 mi path |
| Most recent | 17 Jun 2025, EF1, 3.7 mi path |
| Deaths / injuries on those paths | 0 / 36 |
| Rating | (E)F0 | (E)F1 | (E)F2 | (E)F3 | (E)F4 | (E)F5 | Unrated |
|---|---|---|---|---|---|---|---|
| Count | 11 | 31 | 16 | 5 | 0 | 0 | 1 |
| Decade | 1950s | 1960s | 1970s | 1980s | 1990s | 2000s | 2010s | 2020s |
|---|---|---|---|---|---|---|---|---|
| Count | 7 | 2 | 5 | 7 | 6 | 3 | 24 | 10 |
Deaths and injuries are for each tornado's whole path, which can run beyond this county. F-scale ratings before February 2007, Enhanced Fujita (EF) after.
How Delaware County compares with its 5 nearest counties
| County | Distance | Overall risk | Score | Top hazard |
|---|---|---|---|---|
| Delaware County (this page) | — | Relatively Moderate | 82.7 | Ice storm |
| Mayes County | 40 km | Relatively Low | 77.6 | Ice storm |
| McDonald County, MO | 47 km | Relatively Low | 64.0 | Ice storm |
| Ottawa County | 47 km | Relatively Low | 76.0 | Ice storm |
| Benton County, AR | 50 km | Relatively Moderate | 88.7 | Ice storm |
| Craig County | 53 km | Relatively Low | 55.5 | Ice storm |
Nearest by distance between county centres. Every county in Oklahoma, ranked.
Vulnerability and resilience
| Social vulnerability | Very High 90.9 |
|---|---|
| Community resilience | Very Low 5.8 |
| Community risk factor | 1.71 |
| Expected annual loss, all hazards | $30 million |
FEMA scales expected losses up where social vulnerability is high (people who may find it harder to prepare, evacuate or recover) and down where community resilience is high. A factor above 1 raises the risk score. For social vulnerability a high rating is worse; for resilience a high rating is better.
Prepare for Delaware County's main hazards
- Right now: National Weather Service alerts for Oklahoma · all official warnings on Global Incident Tracker.
- Ice storm: Power outages now · Carbon monoxide in winter
- Heat wave: Heatstroke warning signs
- Wildfire: US wildfires now · Wildfire smoke: what protects you
- Your property's flood zone: FEMA Flood Map Service Center ↗ — this page cannot tell you that.
- Official preparedness guidance: Ready.gov ↗ and your county emergency management office.
What this page shows, and what it misses
FEMA's National Risk Index rates a whole county against every other US county; it is a planning-level estimate for nationwide comparison, not a flood-zone map and not a substitute for a local risk assessment or the risk to one home. Declarations are presidential disaster, emergency and fire management declarations that named this county; state declarations and SBA or USDA designations are not included. Tornadoes are counted when the county is one of up to four listed on the track; 670 tornadoes that crossed a state line carry no county list in NOAA's file and are left out.
Federal Emergency Management Agency (FEMA), National Risk Index Dataset: National Risk Index Counties - v1.20.0 (December 2025). Retrieved from https://services.arcgis.com/XG15cJAlne2vxtgt/ArcGIS/rest/services/National_Risk_Index_Counties/FeatureServer/0/query on November 2, 2026, 1:20 PM EST. This product uses the Federal Emergency Management Agency’s National Risk Index dataset API or downloadable datasets 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).
Federal Emergency Management Agency (FEMA), OpenFEMA Dataset: Disaster Declarations Summaries - v2, retrieved from https://www.fema.gov/api/open/v2/DisasterDeclarationsSummaries on November 2, 2026, 1:21 PM EST. 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).
Tornado records: NOAA/NWS Storm Prediction Center, Severe Weather Database, tornadoes 1950–2025 (https://www.spc.noaa.gov/wcm/data/1950-2025_actual_tornadoes.csv, downloaded 2 November 2026). Public domain; not endorsed by NOAA. Compiled by Global Incident Tracker.
Questions about Delaware County
What natural disasters is Delaware County, Oklahoma most at risk from?
Delaware County, Oklahoma has a Relatively Moderate natural-hazard risk rating in FEMA's National Risk Index (v1.20, December 2025): a score of 82.7 out of 100, higher than about 82% of US counties, with ice storms, heat waves and wildfires scoring highest of its 18 hazards and $30 million a year in expected losses.
How many federal disaster declarations has Delaware County had?
OpenFEMA lists 31 federal disaster declarations that included Delaware County since 1973, not counting 2 for COVID-19; the latest is DR-4791-OK (Severe Storms, Straight-Line Winds, Tornadoes, and Flooding, declared 14 June 2024). Another 24 Oklahoma declarations were made statewide without a county list.
How many tornadoes have hit Delaware County?
NOAA's Storm Prediction Center recorded 64 tornadoes touching Delaware County from 1950 to 2025. The deadliest: 22 May 2011, EF2, 2.9 mi path, 0 killed, 12 injured (deaths and injuries are for the whole path).
Is the National Risk Index a flood zone map?
No. The National Risk Index is a planning-level estimate for a whole county, built for nationwide comparison. It does not tell you the flood zone or the risk of a single property: for that, look up the address on FEMA's Flood Map Service Center (msc.fema.gov) and ask your local floodplain manager.