Weather experts will visit Butler County to investigate multiple sites where tornadoes may have caused damage on Thursday evening.

“At this point, it looks like there could have very well been a tornado,” said Michael Brown, a meteorologist for the National Weather Service of Pittsburgh.

Thunderstorms arrived in the county late Thursday evening, and some residents experienced heavy damage in isolated areas.

Along Mercer Road, there were multiple trees that had fallen onto wires along the road. Some parts of Mercer Road were restricted to one lane because of debris still hanging on wires.

Mercer Road resident Chip Grubbs of Butler Township said he, his neighbors and Butler Township firefighters worked for hours to clear a large tree that had fallen onto the road.

“The neighbors really helped,” Grubbs said. “There were five people here, and they brought their saws.”

Grubbs said the effort cleared most of the road, but the tree remained on the line through Friday morning, until the utility company could come and inspect the site.

“I'm going to wait for them to clear this line, and then I'll cut it up,” he said. “I'll be here a while.”

Grubbs said he did not see the tree come down. He said he and his wife received the first tornado warning alert on their phones, initially ignoring it.

The weather service issued a first tornado warning alert around 7:30 p.m. Thursday, which was followed by a second about 10 to 15 minutes later.

When the second alert came, they decided to head to the basement.

“We got downstairs and heard a thud,” Grubbs said.

Grubbs said he was thankful the tree did not fall the opposite direction as it would have landed squarely on his home.

According to the county's data, between 7:45 and 9:37 p.m., there were 11 calls received by dispatchers for “downed” objects, which could be utility poles, trees or other items, but were not specified on the reports.

Grubbs said his home saw no damage, but a good chunk of his yard was torn up in the cluster of roots that had come away with the upended tree. Grubbs said there were other indicators of the severity of the weather event that hit his neighborhood.

“It ripped my American flag off, and it pushed in the lattice work on my deck,” he said. “It actually ripped my plants out of the pots.”

The damage Grubbs experienced on his property is the reason weather experts will be drawn to the county.

According to the weather service, there were five confirmed tornadoes last weekend in the Greater Pittsburgh Region, and with Thursday's storm there are several possible tornadoes.

As of Friday evening, National Weather Service experts surveyed northern portions of Butler County. Their investigation remained inconclusive regarding the possible tornado.

According to Brown, one report involved a possible tornado that moved into the county from Beaver County, while other investigations will be conducted on damage found entirely within the county. He said some areas being investigated include Slippery Rock, East Butler and Butler Township.

Brown said the ideal conditions arrived in a small window during the night. He said a tornado needs instability from a warm front and wind that generally has increasing speeds higher in the air.

Brown said those conditions were not met for a majority of the storms Thursday, but a short time after the thunderstorms hit in the evening, a cold front came with the necessary wind speeds.

“Pretty fast, faster than your typical speeds, it's all those ingredients coming together,” he said. “It has to be just right for tornadoes.”

Brown said in the coming days, the weather service is expecting things to remain cool and cloudy, which should continue as winter comes.