The National Weather Service said an EF-1 tornado briefly touched down in West Cocalico Township. An EF-1 tornado has winds up to 110 mph.
An entire neighborhood on Kline Road Denver in West Cocalico Township was hit hard, with some comparing the noise on Sunday night to a freight train.
Winds tore roofs off of homes, uprooted massive trees and ripped down power lines.
Nearby in the community of Stevens, also in West Cocalico Township, residents of the Oak Ridge Park mobile home community also saw extensive damage.
Lisa Williams lost part of her roof.
"The whole house was shaking. I went to hold the door to close the window or something. It happened so fast - and I saw his shingles flying off and my roof came down - and I just yelled for Jesus," she said.
Many were still without power on Monday afternoon.
Residents on Kline Road say two neighbors in their 90s suffered minor injuries from flying debris.
Lancaster County officials toured the damage with The National Weather Service.
Michael Jurewicz of the NWS explained what they look for when trying to determine if a tornado touched down.
"What we typically look for on these damage surveys are patterns of damage. How objects are laid down. Are they blown down in a straight line? Are they a chaotic pattern? Is there a convergence to it?"