The tornado was initially confirmed by radar near Hartly at 17:53 EDT (21:53 UTC) on August 20, about 23 km (14 miles) west of Dover and moving east at 48 km/h (30 mph).
At 18:11 EDT (22:11 UTC), the warning described a confirmed large and extremely dangerous tornado over Dover, moving east at 56 km/h (35 mph). The warning was designated a Particularly Dangerous Situation and carried a considerable damage threat.
At 18:18 EDT (22:18 UTC), the tornado was located over Dover near Dover Speedway and moving northeast at 48 km/h (30 mph). A trained spotter reported a rain-wrapped tornado on the ground with flying debris, while tornado damage was being reported elsewhere in the city.
A local State of Emergency went into effect at 18:20 EDT (22:20 UTC) on August 20 for Dover. Significant damage was reported along the Division Street and Loockerman Street corridor and in parts of North DuPont Highway.
The tornado caused structural damage at the Kraft Foods facility and damaged the roofs of the Days Inn and Superlodge on North DuPont Highway. Occupants of the two hotels were evacuated safely, and no serious injuries were reported in Dover.
Damage was also reported at the Dover Little League complex on Electric Avenue, where fencing and poles were brought down and a tree fell onto the scoreboard. Numerous trees and large branches blocked roads elsewhere in the city.
Flooded roads and power outages created additional hazards. Traffic signals stopped functioning at numerous intersections, and police asked residents to avoid unnecessary travel and treat intersections with dark signals as four-way stops.
Severe storms also caused damage in York and Lancaster counties in Pennsylvania. The roof of Eastern York High School was significantly damaged shortly before 16:30 EDT (20:30 UTC), while approximately 50 student-athletes were inside the gym.
No injuries were reported at the school. Emergency personnel inspected the building after the storm and restricted access to the damaged areas.
Six townhomes were damaged in the Winding Way area of Lower Windsor Township. One resident sustained a minor injury and was taken to hospital, while at least 13 residents were displaced.
In Lancaster County, Columbia Borough declared a State of Emergency effective at 18:00 EDT (22:00 UTC) after severe building damage, collapsed walls, roof damage and downed trees and wires were reported. A nighttime curfew began at 22:00 EDT on August 20 (02:00 UTC on August 21), and an emergency shelter was opened at St. Peter’s Parish Hall.
Preliminary storm reports documented severe structural damage in Columbia, including collapsed walls, a collapsed shed and shingles removed from several roofs. The State of Emergency was expected to remain in effect while authorities secured damaged buildings and cleared affected roads.
The Storm Prediction Center catalogued the Pennsylvania incidents as preliminary wind-damage reports. NWS State College scheduled surveys of Eastern York County and Columbia beginning at 08:00 EDT (12:00 UTC) on August 21, with a final assessment expected that evening.
No tornado rating or final damage-path determination had been issued for the Pennsylvania sites at the time of writing. The Dover tornado had also not yet received a final EF rating or surveyed path.
References:
1 Preliminary Storm Survey Scheduled for Eastern York County and Columbia — NWS — August 21, 2026
2 Public Safety Announcement: State of Emergency Declared — Columbia Borough Police Department — August 20, 2026
3 York County storm-damage update — York County Office of Emergency Management — August 20, 2026