Counties with the most tornadoes in Pennsylvania

It's been a busy year for tornadoes in the U.S. According to the National Oceanic and Atmospheric Administration, as many as 1,155 twisters have touched down across the country since the start of the year, above the average for this time of year.

A single day can drive up tornado counts. March 31, 2023, accounted for 163 tornadoes across the Midwest and South. Tornado activity usually peaks in the spring and early summer, and the pace of tornadoes usually slows around late summer. A smaller-scale second tornado season emerges in the fall, mostly in the Gulf Coast states.

Stacker used data from NOAA's National Centers for Environmental Information to find the counties in Pennsylvania that have experienced the most tornadoes since 2000. While data is available going back to 1950, tornado tracking by the National Weather Service became more robust and accurate in the 1990s. Since counties can vary in size, they are ranked by the number of tornadoes per 100 square miles. Counties that experienced less than five tornadoes are not included.

The counties that encounter the most tornadoes aren't all in the infamous Tornado Alley. When adjusted for county area, the top 10 counties that experienced the most tornadoes since 2000 are from nine different states, all in the Southeast with the exception of Cleveland County, Oklahoma.

Research has shown that Tornado Alley is shifting due to warming temperatures fueled by climate change. In the future, the Southeast could become the region that receives the bulk of the country's tornadoes. It's a concerning trend as the South is more populated than the Great Plains and has a higher concentration of mobile homes than other parts of the country, making the storms potentially deadlier and costlier.

As of August 2023, 75 people have died from tornadoes this year, and over 60% of those deaths occurred in mobile homes.

The best way to stay protected during tornadoes is to have multiple ways of receiving storm updates including social media, radio, television, and sirens, and to immediately seek shelter in a basement or interior room without windows when a tornado watch escalates to a warning.

Read on to see which counties experience the most tornadoes in Pennsylvania.