The tornado is rated an EF2 with winds estimated at 120-125 mph. Damage is concentrated to an area 4.7 miles long, 400 yards wide.
It caused an estimated $8 million in damage.
Lancaster County officials say up to 50 buildings were damaged, and many of those impacted were members of the Amish community.
By Thursday morning, Amish families from miles away arrived to help rebuild.
They say they plan to repair those structures that are still sound and tear down others, like a heavily-damaged, one-room school house. They plan to start building a new school house on Friday.
On Thursday night, Paul Miller watched, with his lights on, as the men finished up some cinder block.
"It's amazing, it's really amazing to watch these guys work, hustle," said Miller. "At one time I couldn't even count the number of guys working."
Chopper 6 HD was over the community of Gap in Salisbury Township, showing a large, red barn in ruins.
A house, another nearby barn and silos were also heavily damaged. Debris littered the area.
It was a narrow path of destruction, a clear indicator of a tornado.
"But it is very narrow. The farm next door, the trees, you have no damage to them, and yet the path the tornado took there was quite a bit of damage, so it was very concentrated.
"It's very rare to have a tornado, particularly of this magnitude, kind of on the ground that long and doing this sort of damage," said Barbara Watson of the National Weather Service.
The cleanup will be extensive, but officials say the storm could've been much more devastating.
"There's actually been no reported injuries that we are aware of so they're definitely very fortunate in this area," said Pennsylvania State Police Trooper Ryan Lawrence.
A command center has been set up at the local fire company. Affected residents arrived in droves for a warm meal or simply some help in the cleanup.
Around 7 p.m., it was shut down for the night, but cases of water remained outside.
"There was hundreds and hundreds of contractors, Amish contractors that have their own businesses that had their guys here today," said Sam Fisher, volunteer. "There was equipment, guys from GAP Power, seen their trucks in here today."
The Amish do not generally buy commercial insurance, but self insure through an agreement sometimes called an Amish Aid Plan.
"They have what they call Amish Aid insurance. It's all based on their religion. Every neighbor comes together and helps every other neighbor out," said Derek Cummings of Intercourse, Pennsylvania.
"They help each other out, their families will be assessed a certain amount if need be to help pay for the cost, and they just do the work themselves," said Randy Gockley, the director of Lancaster County Office of Emergency Management.
There was a crowd attending an auction inside of a barn what was hit by the tornado, according to Derick Cummings, who works for an Amish construction firm.
"There carriages outside flipped over," he said, but added that by the "grace of God" there was no one injured.