Loudoun County, Virginia Natural Disaster Risk
FEMA National Risk Index assessment · VA
LowComposite Risk Score
National percentile: 78th
Loudoun County faces low composite natural disaster risk (NRI Risk Index score 78.1, 78th national percentile), driven primarily by heat wave and winter weather exposure. Expected annual loss across all 18 hazard types is $61M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
Overall natural disaster risk in Loudoun County is low, with a National Risk Index score of 78.1 out of 100 — placing it in the 78th national percentile and below the national average for natural-disaster risk. The score blends Expected Annual Loss, Social Vulnerability, and Community Resilience across all 18 FEMA hazard types.
Risk here concentrates in heat wave (prolonged periods of extreme heat that threaten health and infrastructure) at Medium risk — $5M in expected annual loss and about 4.52 events per year; winter weather (heavy snow, blizzards, and hazardous winter conditions) at High risk — $655K in expected annual loss and about 12.33 events per year; and lightning (electrical discharges from storms that ignite fires and cause casualties) at High risk — $2M in expected annual loss and about 38.50 events per year. Across all hazards, FEMA estimates $61M in expected annual loss for a population of 419K.
Beyond physical exposure, Loudoun County has a very low social vulnerability rating (how susceptible the population is to harm) and a very high community resilience rating (its capacity to prepare for and recover from disasters). A less vulnerable population paired with strong resilience helps the community absorb and recover from events.
The county's disaster history tells the same story: Loudoun County has received 16 federal disaster declarations since 1972, including 5 for hurricane events and 4 for snowstorm events. The most recent was Severe Winter Storm (winter storm), declared in January 2026.
Among 133 Virginia counties, Loudoun County ranks #10 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Heat Wave | Medium | 4.52 / yr | $5M |
| Winter Weather | High | 12.33 / yr | $655K |
| Lightning | High | 38.50 / yr | $2M |
| Strong Wind | High | 7.69 / yr | $3M |
| Riverine Flood | Medium | 3.04 / yr | $37M |
| Hurricane | Low | 0.09 / yr | $3M |
| Earthquake | Low | 0.00 / yr | $2M |
| Hail | Medium | 3.92 / yr | $1M |
| Tornado | Medium | 0.35 / yr | $5M |
| Drought | Medium | 4.06 / yr | $1M |
| Landslide | Very Low | 0.36 / yr | $2K |
| Wildfire | Very Low | 0.00 / yr | $34K |
| Ice Storm | Very Low | 0.58 / yr | $41K |
| Cold Wave | Low | 1.76 / yr | $493K |
| Avalanche | Very Low | 0.01 / yr | $55 |
| Coastal Flood | Very Low | 0.00 / yr | $0 |
| Tsunami | Very Low | 0.00 / yr | $0 |
| Volcanic Activity | Very Low | 0.00 / yr | $0 |
Disaster History
Loudoun County has received 16 federal disaster declarations since 1972, most recently Severe Winter Storm in January 2026. Most frequent causes: Hurricane (5), Snowstorm (4), Biological (2).
| Declared | Type | Disaster |
|---|---|---|
| January 2026 | Winter Storm | Severe Winter Storm |
| April 2020 | Biological | Covid-19 Pandemic |
| March 2020 | Biological | Covid-19 |
| September 2018 | Hurricane | Hurricane Florence |
| March 2016 | Snowstorm | Severe Winter Storm and Snowstorm |
| November 2012 | Hurricane | Hurricane Sandy |
| October 2012 | Hurricane | Hurricane Sandy |
| April 2010 | Snowstorm | Severe Winter Storms and Snowstorms |
| September 2005 | Hurricane | Hurricane Katrina Evacuation |
| September 2003 | Hurricane | Hurricane Isabel |
Showing the 10 most recent of 16 declarations.
Source: FEMA Disaster Declarations Summaries (OpenFEMA).
Frequently Asked Questions
What is the overall natural disaster risk for Loudoun County?
Loudoun County has a composite FEMA National Risk Index score of 78.1 out of 100, placing it in the Low category and the 78th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Loudoun County?
The three highest-rated hazards are Heat Wave (Medium, $5M EAL), Winter Weather (High, $655K EAL), Lightning (High, $2M EAL). These account for most of the county's expected annual losses.
How does Loudoun County compare to other Virginia counties?
Loudoun County ranks #10 of 133 Virginia counties for overall natural disaster risk, with a low rating.
How many federally declared disasters has Loudoun County had?
FEMA records 16 federal disaster declarations for Loudoun County since 1972, most often 5 for hurricane events and 4 for snowstorm events. The most recent was Severe Winter Storm, declared in January 2026.
What does Expected Annual Loss (EAL) mean?
EAL is FEMA's estimate of average annual dollar losses from natural hazards, calculated from historical event data and exposure models. Loudoun County's $61M EAL is a statistical average, not a guarantee for any specific year or address.