Lancaster County, Pennsylvania Natural Disaster Risk
FEMA National Risk Index assessment · PA
HighComposite Risk Score
National percentile: 95th
Lancaster County faces high composite natural disaster risk (NRI Risk Index score 95.0, 95th national percentile), driven primarily by winter weather and riverine flood exposure. Expected annual loss across all 18 hazard types is $170M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
Overall natural disaster risk in Lancaster County is high, with a National Risk Index score of 95.0 out of 100 — placing it in the 95th national percentile and in the upper tier of natural-disaster risk nationally. The score blends Expected Annual Loss, Social Vulnerability, and Community Resilience across all 18 FEMA hazard types.
Risk here concentrates in winter weather (heavy snow, blizzards, and hazardous winter conditions) at Very High risk — $2M in expected annual loss and about 12.27 events per year; riverine flood (rivers and streams overflowing their banks after heavy rain or snowmelt) at High risk — $111M in expected annual loss and about 3.43 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 36.02 events per year. Across all hazards, FEMA estimates $170M in expected annual loss for a population of 553K.
Beyond physical exposure, Lancaster County has a medium social vulnerability rating (how susceptible the population is to harm) and a 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: Lancaster County has received 22 federal disaster declarations since 1972, including 7 for flood events and 4 for snowstorm events. The most recent was Covid-19 Pandemic (biological), declared in March 2020.
Among 67 Pennsylvania counties, Lancaster County ranks #4 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Winter Weather | Very High | 12.27 / yr | $2M |
| Riverine Flood | High | 3.43 / yr | $111M |
| Lightning | High | 36.02 / yr | $2M |
| Hurricane | High | 0.08 / yr | $24M |
| Heat Wave | Medium | 5.26 / yr | $5M |
| Earthquake | Medium | 0.00 / yr | $10M |
| Strong Wind | High | 6.71 / yr | $2M |
| Cold Wave | High | 1.16 / yr | $8M |
| Drought | Medium | 4.34 / yr | $2M |
| Hail | Medium | 2.71 / yr | $1M |
| Ice Storm | Medium | 1.21 / yr | $471K |
| Tornado | Medium | 0.59 / yr | $4M |
| Landslide | Low | 0.55 / yr | $8K |
| Wildfire | Very Low | 0.00 / yr | $21K |
| Avalanche | Very Low | 0.01 / yr | $33 |
| 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
Lancaster County has received 22 federal disaster declarations since 1972, most recently Covid-19 Pandemic in March 2020. Most frequent causes: Flood (7), Snowstorm (4), Hurricane (4).
| Declared | Type | Disaster |
|---|---|---|
| March 2020 | Biological | Covid-19 Pandemic |
| March 2020 | Biological | Covid-19 |
| March 2016 | Snowstorm | Severe Winter Storm and Snowstorm |
| February 2014 | Severe Ice Storm | Severe Winter Storm |
| October 2012 | Hurricane | Hurricane Sandy |
| September 2011 | Flood | Tropical Storm Lee |
| September 2011 | Flood | Remnants of Tropical Storm Lee |
| April 2010 | Snowstorm | Severe Winter Storms and Snowstorms |
| June 2006 | Severe Storm | Severe Storms, Flooding, and Mudslides |
| September 2005 | Hurricane | Hurricane Katrina |
Showing the 10 most recent of 22 declarations.
Source: FEMA Disaster Declarations Summaries (OpenFEMA).
Frequently Asked Questions
What is the overall natural disaster risk for Lancaster County?
Lancaster County has a composite FEMA National Risk Index score of 95.0 out of 100, placing it in the High category and the 95th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Lancaster County?
The three highest-rated hazards are Winter Weather (Very High, $2M EAL), Riverine Flood (High, $111M EAL), Lightning (High, $2M EAL). These account for most of the county's expected annual losses.
How does Lancaster County compare to other Pennsylvania counties?
Lancaster County ranks #4 of 67 Pennsylvania counties for overall natural disaster risk, with a high rating.
How many federally declared disasters has Lancaster County had?
FEMA records 22 federal disaster declarations for Lancaster County since 1972, most often 7 for flood events and 4 for snowstorm events. The most recent was Covid-19 Pandemic, declared in March 2020.
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. Lancaster County's $170M EAL is a statistical average, not a guarantee for any specific year or address.