By CBS3 Staff

PHILADELPHIA (CBS) — Severe storms that have been classified as a derecho left three people dead in Montgomery County after quickly sweeping through the Delaware Valley on Wednesday. A tornado warning was in effect for Philadelphia and surrounding counties in Pennsylvania and New Jersey and expired at 7:45 p.m.

Video tweeted by The Philadelphia Inquirer’s Chris Brennan shows ominous clouds over Philadelphia Wednesday evening.

One person died after a massive tree fell on the clubhouse at the Philmont Country Club in Huntingdon Valley.

(Credit: CBS3)

Two other people died in Lower Merion Township after trees fell on their cars.

All three deaths are separate incidents.

The severe storms left hundreds of thousands of customers without power, toppled multiple trees and ripped off roofs across the region.

PHOTOS: SEVERE STORMS LEAVE BEHIND PATH OF DESTRUCTION

In Lansdale, The Crossings at Stanbridge suffered a partial roof collapse when the storms barreled through the area. Witnesses say it happened in an instant as the roof started peeling and then fell right in front of the building, breaking a light post in half.

No one was injured at the apartment complex.

The six-story building holds about 150 units and all of those families are being evacuated as a precaution for a couple of days.

“The Red Cross is here. We have buses to move them. It’s just a matter of when to get everyone back inside,” said Gavin Butler, deputy chief of the Lansdale Fairmount Fire Company.

Joe Rossi’s car is stuck under the rubble. He wonders how differently this could have turned out if he walked to his car moments earlier.

“She said wait until the storm is over, then five seconds after that, it slammed right on top of my car,” Rossi said.

He’s counting his blessings.

“I’m just happy I’m OK. I think I should play the lottery today,” Rossi said.

“It went really fast from this is a little bit of a wind storm to I’ve never seen anything like this in my whole life,” said Curtis Childs of Bryn Athyn.

In Bryn Athyn borough, just about every block suffered very large downed trees.

“It just got so dark that I said to my husband, ‘I think we need to get in the basement,'” said Paige Austin.

Austin’s car was hit by a falling tree but her house was spared.

“It’s just everyone offering tarps and help. All the neighbors are coming out to help,” she said.

Like nearly all of his neighbors, Childs is without power.

“We are trying to get our generator fixed so hopefully, we don’t lose all of our food, but if we lose it, we lose it. There are bigger things in life,” Childs said.

Meanwhile, over 400,000 customers across the region lost power after storms packing 70 to 80 mph winds hit the area.

The storm brought multiple trees down across the area.

(credit: CBS3)

A massive one toppled over in the Roxborough section of Philadelphia.

(credit: CBS3)

In Haddonfield, Camden County, a large tree fell on several cars along Kings Highway.

The tree’s impact was so powerful, a couple of cars lifted off the ground. No one was hurt.

Across the region, an 83 mph wind gust was reported in Reading and a 72 mph one was recorded in Camden. Northeast Philadelphia had to deal with 68 mph winds, while the Philadelphia International Airport recorded 61 mph.

Video shows the storm bringing monsoon-like conditions when it moved through.

The National Weather Service has classified the severe storms that moved through as a derecho.

According to the National Weather Service, a derecho is a “widespread, long-lived wind storm that is associated with a band of rapidly moving showers or thunderstorms. Although a derecho can produce destruction similar to the strength of tornadoes, the damage typically is directed in one direction along a relatively straight swath. As a result, the term ‘straight-line wind damage’ sometimes is used to describe derecho damage. By definition, if the wind damage swath extends more than 240 miles and includes wind gusts of at least 58 mph or greater along most of its length, then the event may be classified as a derecho.”

CBS3’s Alecia Reid and Alexandria Hoff contributed to this report.