Loudoun County, Virginia: Natural Disaster Risk and History
Loudoun County, Virginia has a Relatively Low natural-hazard risk rating in FEMA's National Risk Index (v1.20, December 2025): a score of 78.1 out of 100, higher than about 78% of US counties, with heat waves, winter storms and lightning scoring highest of its 18 hazards and $61 million a year in expected losses.
OpenFEMA lists 14 federal disaster declarations that included Loudoun County since 1972, not counting 2 for COVID-19; the latest is EM-3631-VA (Severe Winter Storm, declared 23 January 2026). NOAA's Storm Prediction Center recorded 25 tornadoes touching Loudoun County from 1950 to 2025.
Live weather alerts for Virginia All official warnings Latest FEMA declarations
Population 418,601 Buildings worth $65 billion Area 527 sq mi Risk rank in Virginia 10 of 133 FIPS 51107
All 18 hazards, highest risk first
FEMA National Risk Index| Hazard | Risk rating | Score | Expected loss a year | How often | Events in record |
|---|---|---|---|---|---|
| Heat wave | Relatively Moderate | 91.1 | $5.2 million | about 4.5 a year | 76 |
| Winter weather | Relatively High | 90.4 | $654,777 | about 12 a year | 234 |
| Lightning | Relatively High | 87.8 | $1.7 million | about 39 a year | 243,501 strikes |
| Strong wind | Relatively High | 87.4 | $2.8 million | about 7.7 a year | 293 |
| Inland flooding | Relatively Moderate | 83.9 | $37 million | about 3 a year | 85 |
| Hurricane | Relatively Low | 80.1 | $3.1 million | about once every 11 years | 28 |
| Earthquake | Relatively Low | 77.9 | $2.2 million | about once every 806 years | — |
| Hail | Relatively Moderate | 76.5 | $1.2 million | about 3.9 a year | 149 |
| Tornado | Relatively Moderate | 74.7 | $4.8 million | about once every 2.9 years | 24 |
| Drought | Relatively Moderate | 74.1 | $1.0 million | about 4.1 a year | 119 |
| Landslide | Very Low | 51.2 | $2,272 | about once every 2.8 years | — |
| Wildfire | Very Low | 37.4 | $34,359 | rarer than once in 1,000 years | — |
| Ice storm | Very Low | 26.9 | $41,051 | about once every 1.7 years | 40 |
| Cold wave | Relatively Low | 24.6 | $493,393 | about 1.8 a year | 33 |
| Avalanche | Very Low | 19.7 | $55 | about once every 100 years | 0 |
| 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 14
Most common: Hurricane 5, Snowstorm 4, Severe Storm 2, Flood 2.
| Decade | Declarations | Incident types |
|---|---|---|
| 1970s | 1 | Flood |
| 1990s | 3 | Snowstorm ×2, Flood |
| 2000s | 4 | Hurricane ×2, Severe Storm ×2 |
| 2010s | 5 | Hurricane ×3, Snowstorm ×2 |
| 2020s | 1 | Winter Storm |
The last 10
Widest declarations that included Loudoun County
- Severe Winter Storm (2026, EM-3631-VA): 133 Virginia counties designated.
- Hurricane Florence (2018, EM-3403-VA): 133 Virginia counties designated.
- Hurricane Sandy (2012, EM-3359-VA): 133 Virginia counties designated.
Named storms in its declarations: Hurricane Florence (2018), Hurricane Sandy (2012), Hurricane Katrina (2005), Hurricane Isabel (2003), Tropical Storm Agnes (1972).
Not counted above: 2 COVID-19 ("Biological") declarations — in 2020 every US county was included. Virginia also had 3 statewide declarations with no county list.
Tornado record since 1950 25
| Tornadoes touching the county | 25 |
|---|---|
| Strongest-rated | (E)F2 ×4 |
| Peak month | June (8) |
| Deadliest | 5 Sep 1979, F2, 0.5 mi path, 0 killed, 2 injured |
| Longest path | 24 Jun 1996, F2, 20 mi path, 0 killed, 1 injured |
| Most recent | 8 Aug 2024, EF1, 4.8 mi path |
| Deaths / injuries on those paths | 0 / 3 |
| Rating | (E)F0 | (E)F1 | (E)F2 | (E)F3 | (E)F4 | (E)F5 | Unrated |
|---|---|---|---|---|---|---|---|
| Count | 15 | 6 | 4 | 0 | 0 | 0 | 0 |
| Decade | 1950s | 1960s | 1970s | 1980s | 1990s | 2000s | 2010s | 2020s |
|---|---|---|---|---|---|---|---|---|
| Count | 0 | 0 | 2 | 2 | 9 | 6 | 3 | 3 |
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 Loudoun County compares with its 5 nearest counties
| County | Distance | Overall risk | Score | Top hazard |
|---|---|---|---|---|
| Loudoun County (this page) | — | Relatively Low | 78.1 | Heat wave |
| Jefferson County, WV | 31 km | Relatively Low | 47.8 | Drought |
| Clarke County | 31 km | Very Low | 6.9 | Drought |
| Montgomery County, MD | 38 km | Relatively Moderate | 91.7 | Winter weather |
| Fairfax City | 39 km | Very Low | 5.3 | Hurricane |
| Manassas Park City | 39 km | Very Low | 4.9 | Hurricane |
Nearest by distance between county centres. Every county in Virginia, ranked.
Vulnerability and resilience
| Social vulnerability | Very Low 10.6 |
|---|---|
| Community resilience | Very High 85.5 |
| Community risk factor | 0.66 |
| Expected annual loss, all hazards | $61 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 Loudoun County's main hazards
- Right now: National Weather Service alerts for Virginia · all official warnings on Global Incident Tracker.
- Heat wave: Heatstroke warning signs
- Winter weather: Power outages now · Carbon monoxide in winter
- Lightning: Weather alerts for Virginia
- 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 Loudoun County
What natural disasters is Loudoun County, Virginia most at risk from?
Loudoun County, Virginia has a Relatively Low natural-hazard risk rating in FEMA's National Risk Index (v1.20, December 2025): a score of 78.1 out of 100, higher than about 78% of US counties, with heat waves, winter storms and lightning scoring highest of its 18 hazards and $61 million a year in expected losses.
How many federal disaster declarations has Loudoun County had?
OpenFEMA lists 14 federal disaster declarations that included Loudoun County since 1972, not counting 2 for COVID-19; the latest is EM-3631-VA (Severe Winter Storm, declared 23 January 2026). Another 3 Virginia declarations were made statewide without a county list.
How many tornadoes have hit Loudoun County?
NOAA's Storm Prediction Center recorded 25 tornadoes touching Loudoun County from 1950 to 2025. The deadliest: 5 Sep 1979, F2, 0.5 mi path, 0 killed, 2 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.