Pennsylvania tornado risk
Philadelphia County has the highest tornado risk in Pennsylvania, scoring 98.7 out of 100 — rated "Relatively High" by FEMA's National Risk Index. NOAA has recorded 253 tornado events across Pennsylvania over the past decade.
| # | County | NRI score | Rating |
NOAA events 2016–2026 |
|---|---|---|---|---|
| 1 | Philadelphia County | 98.7 | Relatively High | 3 |
| 2 | Montgomery County | 95.6 | Relatively High | 4 |
| 3 | Delaware County | 92.5 | Relatively High | 1 |
| 4 | Bucks County | 92.1 | Relatively High | 12 |
| 5 | Allegheny County | 91.2 | Relatively High | 12 |
| 6 | Berks County | 90.6 | Relatively High | 8 |
| 7 | Chester County | 88 | Relatively Moderate | 2 |
| 8 | Lehigh County | 87.4 | Relatively Moderate | 5 |
| 9 | Luzerne County | 81.6 | Relatively Moderate | 3 |
| 10 | Northampton County | 80.9 | Relatively Moderate | 2 |
| 11 | Dauphin County | 79.8 | Relatively Moderate | 4 |
| 12 | Lancaster County | 79.8 | Relatively Moderate | 7 |
| 13 | Lebanon County | 70.3 | Relatively Moderate | 2 |
| 14 | Fayette County | 68.8 | Relatively Moderate | 9 |
| 15 | Cumberland County | 68.2 | Relatively Moderate | 2 |
| 16 | Lackawanna County | 68.1 | Relatively Moderate | 6 |
| 17 | Erie County | 66.6 | Relatively Moderate | 4 |
| 18 | Schuylkill County | 66.2 | Relatively Moderate | 2 |
| 19 | Monroe County | 65.9 | Relatively Moderate | 1 |
| 20 | Cambria County | 63.9 | Relatively Low | 5 |
| 21 | Butler County | 59.8 | Relatively Low | 9 |
| 22 | Blair County | 58.9 | Relatively Low | 0 |
| 23 | Beaver County | 56.6 | Relatively Low | 9 |
| 24 | Westmoreland County | 55.7 | Relatively Low | 17 |
| 25 | Mercer County | 55.3 | Relatively Low | 4 |
| 26 | Crawford County | 52.5 | Relatively Low | 6 |
| 27 | Lycoming County | 50.4 | Relatively Low | 2 |
| 28 | Washington County | 49.8 | Relatively Low | 15 |
| 29 | York County | 47.6 | Relatively Low | 5 |
| 30 | Susquehanna County | 47 | Relatively Low | 3 |
| 31 | Northumberland County | 46.9 | Relatively Low | 1 |
| 32 | Adams County | 46.2 | Relatively Low | 1 |
| 33 | Franklin County | 46.2 | Relatively Low | 2 |
| 34 | Centre County | 42.8 | Relatively Low | 2 |
| 35 | Indiana County | 42.6 | Relatively Low | 7 |
| 36 | Mifflin County | 41.8 | Relatively Low | 1 |
| 37 | Clearfield County | 40.7 | Relatively Low | 0 |
| 38 | Carbon County | 37.9 | Relatively Low | 1 |
| 39 | Lawrence County | 37.7 | Relatively Low | 1 |
| 40 | Snyder County | 36.9 | Relatively Low | 3 |
| 41 | Columbia County | 36.1 | Relatively Low | 1 |
| 42 | Somerset County | 35.5 | Relatively Low | 3 |
| 43 | Greene County | 34.7 | Relatively Low | 5 |
| 44 | Venango County | 34.5 | Relatively Low | 3 |
| 45 | Armstrong County | 34.2 | Relatively Low | 2 |
| 46 | Union County | 33.7 | Relatively Low | 4 |
| 47 | Bradford County | 31.6 | Relatively Low | 5 |
| 48 | Perry County | 31.6 | Relatively Low | 1 |
| 49 | Jefferson County | 31.2 | Relatively Low | 4 |
| 50 | Wayne County | 30.4 | Relatively Low | 2 |
| 51 | Clarion County | 28.8 | Relatively Low | 8 |
| 52 | Pike County | 27.8 | Relatively Low | 0 |
| 53 | Clinton County | 27.3 | Relatively Low | 1 |
| 54 | Huntingdon County | 27.1 | Relatively Low | 1 |
| 55 | Juniata County | 26.9 | Relatively Low | 2 |
| 56 | Bedford County | 26 | Very Low | 2 |
| 57 | McKean County | 24.5 | Very Low | 0 |
| 58 | Tioga County | 24 | Very Low | 2 |
| 59 | Warren County | 21.9 | Very Low | 5 |
| 60 | Wyoming County | 20.6 | Very Low | 1 |
| 61 | Montour County | 20.3 | Very Low | 0 |
| 62 | Elk County | 18.1 | Very Low | 7 |
| 63 | Fulton County | 15.5 | Very Low | 4 |
| 64 | Potter County | 15 | Very Low | 0 |
| 65 | Forest County | 14 | Very Low | 5 |
| 66 | Sullivan County | 12.2 | Very Low | 2 |
| 67 | Cameron County | 10.8 | Very Low | 0 |
Source: FEMA National Risk Index v1.20.0, December 2025. Scores are 0–100 percentile rankings among all US counties. See the methodology page for definitions. Download the full CSV for all counties.
Tornado risk nationally:
Other hazard risks in Pennsylvania:
Frequently asked questions
What is the highest tornado risk county in Pennsylvania?
Philadelphia County, PA has the highest tornado risk in Pennsylvania, with a FEMA National Risk Index score of 98.7 out of 100 (rated "Relatively High").
What causes tornado risk in Pennsylvania?
Tornado risk concentrates in the central and southern plains ("Tornado Alley") and the Southeast ("Dixie Alley"), where atmospheric conditions favor supercell thunderstorm development. The highest scores often belong to counties with significant mobile home and manufactured housing stock, which carries disproportionate tornado mortality risk.