Union County, Pennsylvania: Natural Disaster Risk and History
Union County, Pennsylvania has a Relatively Low natural-hazard risk rating in FEMA's National Risk Index (v1.20, December 2025): a score of 55.2 out of 100, higher than about 55% of US counties, with strong winds, winter storms and hurricanes scoring highest of its 18 hazards and $14 million a year in expected losses.
OpenFEMA lists 16 federal disaster declarations that included Union County since 1972, not counting 2 for COVID-19; the latest is DR-4815-PA (Tropical Storm Debby, declared 11 September 2024). NOAA's Storm Prediction Center recorded 12 tornadoes touching Union County from 1950 to 2025.
Live weather alerts for Pennsylvania All official warnings Latest FEMA declarations
Population 42,665 Buildings worth $7.7 billion Area 321 sq mi Risk rank in Pennsylvania 50 of 67 FIPS 42119
All 18 hazards, highest risk first
FEMA National Risk Index| Hazard | Risk rating | Score | Expected loss a year | How often | Events in record |
|---|---|---|---|---|---|
| Strong wind | Relatively Moderate | 83.4 | $1.2 million | about 3.1 a year | 118 |
| Winter weather | Relatively Moderate | 79.9 | $164,578 | about 13 a year | 243 |
| Hurricane | Relatively Low | 74.3 | $705,718 | about once every 19 years | 14 |
| Inland flooding | Relatively Low | 71.8 | $11 million | about 1.3 a year | 37 |
| Landslide | Relatively Low | 64.6 | $2,933 | about once every 3.6 years | — |
| Lightning | Relatively Low | 53.4 | $208,082 | about 34 a year | 58,180 strikes |
| Heat wave | Relatively Low | 44.7 | $225,418 | about 2.8 a year | 46 |
| Earthquake | Very Low | 43.6 | $149,172 | rarer than once in 1,000 years | — |
| Tornado | Relatively Low | 33.7 | $498,539 | about once every 8.5 years | 12 |
| Avalanche | Very Low | 33.5 | $108 | about once every 100 years | 0 |
| Cold wave | Very Low | 20.8 | $188,062 | about 1.4 a year | 27 |
| Ice storm | Very Low | 19.9 | $12,691 | about once every 9.7 years | 7 |
| Wildfire | Very Low | 10.4 | $2,574 | rarer than once in 1,000 years | — |
| Hail | Very Low | 9.8 | $23,905 | about 1.6 a year | 60 |
| Drought | No Rating | 0.0 | — | — | 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 16
Most common: Flood 6, Hurricane 3, Severe Storm 3, Snowstorm 2.
| Decade | Declarations | Incident types |
|---|---|---|
| 1970s | 2 | Flood ×2 |
| 1980s | 1 | Tornado |
| 1990s | 5 | Flood ×2, Snowstorm ×2, Severe Storm |
| 2000s | 4 | Hurricane ×2, Severe Storm ×2 |
| 2010s | 3 | Flood ×2, Hurricane |
| 2020s | 1 | Tropical Storm |
The last 10
Widest declarations that included Union County
- Hurricane Sandy (2012, EM-3356-PA): 67 Pennsylvania counties designated.
- Hurricane Katrina (2005, EM-3235-PA): 67 Pennsylvania counties designated.
- Tropical Depression Ivan (2004, DR-1557-PA): 67 Pennsylvania counties designated.
Named storms in its declarations: Tropical Storm Debby (2024), Hurricane Sandy (2012), Tropical Storm Lee (2011), Hurricane Katrina (2005), Tropical Depression Ivan (2004), Tropical Depression Frances (2004), Tropical Depression Dennis (1999), Tropical Storm Agnes (1972).
Not counted above: 2 COVID-19 ("Biological") declarations — in 2020 every US county was included. Pennsylvania also had 5 statewide declarations with no county list.
Tornado record since 1950 12
| Tornadoes touching the county | 12 |
|---|---|
| Strongest-rated | (E)F3 ×1 |
| Peak month | July (6) |
| Deadliest | 31 May 1985, F3, 19 mi path, 6 killed, 60 injured |
| Longest path | 31 May 1985, F3, 19 mi path, 6 killed, 60 injured |
| Most recent | 2 Jul 2023, EF1, 1.5 mi path |
| Deaths / injuries on those paths | 6 / 60 |
| Rating | (E)F0 | (E)F1 | (E)F2 | (E)F3 | (E)F4 | (E)F5 | Unrated |
|---|---|---|---|---|---|---|---|
| Count | 3 | 8 | 0 | 1 | 0 | 0 | 0 |
| Decade | 1950s | 1960s | 1970s | 1980s | 1990s | 2000s | 2010s | 2020s |
|---|---|---|---|---|---|---|---|---|
| Count | 0 | 0 | 0 | 1 | 3 | 2 | 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 Union County compares with its 5 nearest counties
| County | Distance | Overall risk | Score | Top hazard |
|---|---|---|---|---|
| Union County (this page) | — | Relatively Low | 55.2 | Strong wind |
| Snyder County | 21 km | Relatively Low | 54.3 | Winter weather |
| Northumberland County | 32 km | Relatively Low | 79.2 | Winter weather |
| Montour County | 35 km | Very Low | 14.7 | Hurricane |
| Lycoming County | 42 km | Relatively Low | 79.6 | Inland flooding |
| Juniata County | 56 km | Very Low | 38.8 | Landslide |
Nearest by distance between county centres. Every county in Pennsylvania, ranked.
Vulnerability and resilience
| Social vulnerability | Relatively High 73.5 |
|---|---|
| Community resilience | Relatively High 72.8 |
| Community risk factor | 1.33 |
| Expected annual loss, all hazards | $14 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 Union County's main hazards
- Right now: National Weather Service alerts for Pennsylvania · all official warnings on Global Incident Tracker.
- Strong wind: Power outages now
- Winter weather: Power outages now · Carbon monoxide in winter
- Hurricane: Is there a hurricane now? · Cyclone preparation
- 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 Union County
What natural disasters is Union County, Pennsylvania most at risk from?
Union County, Pennsylvania has a Relatively Low natural-hazard risk rating in FEMA's National Risk Index (v1.20, December 2025): a score of 55.2 out of 100, higher than about 55% of US counties, with strong winds, winter storms and hurricanes scoring highest of its 18 hazards and $14 million a year in expected losses.
How many federal disaster declarations has Union County had?
OpenFEMA lists 16 federal disaster declarations that included Union County since 1972, not counting 2 for COVID-19; the latest is DR-4815-PA (Tropical Storm Debby, declared 11 September 2024). Another 5 Pennsylvania declarations were made statewide without a county list.
How many tornadoes have hit Union County?
NOAA's Storm Prediction Center recorded 12 tornadoes touching Union County from 1950 to 2025. The deadliest: 31 May 1985, F3, 19 mi path, 6 killed, 60 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.