Overview
- A line of severe thunderstorms moved through south‑central Pennsylvania on Thursday, Aug. 20, prompting multiple National Weather Service Severe Thunderstorm Warnings for Lancaster, York and Adams counties.
- Radar indicated rotation in one storm and the NWS issued a Tornado Warning for northeastern Lancaster County near East Petersburg as the storm moved northeast at roughly 30–40 mph.
- Warnings cited specific hazards including radar‑indicated 60 mph wind gusts, sub‑inch hail and very heavy rain with flash‑flood potential and named stretches of Interstate 83 and the Pennsylvania Turnpike.
- Local reports and viewer videos described structural damage in Columbia and parts of York County, including a badly damaged roof at Eastern York High School in Wrightsville, downed trees and power lines.
- Officials have urged people in warned areas to take shelter and avoid flooded roadways and said NWS damage surveys are underway to determine whether any tornadoes occurred and to document the full extent of damage.