A line of powerful thunderstorms roared through the Baltimore region on Monday evening, downing trees and utility poles and leaving thousands of customers without power and some motorists trapped in their vehicles.

As of 12:30 a.m., Baltimore Gas and Electric was reporting that nearly 70,000 customers were affected by power outages. That includes more than 26,000 in Baltimore County, nearly 28,000 in Carroll County, 6,000 in Baltimore City, more than 5,300 in Harford County and over 700 in Anne Arundel County.

WJZ-TV reported that two people had to be rescued from their White Hall home after a tree fell on it.

The news station also reported that dozens were trapped in their cars after storms knocked utility poles onto vehicles along Route 140 in Westminster. BGE was working to de-energize the powerlines so that the occupants could be removed.

“This is catastrophic damage,” BGE spokesman Nick Alexopolos said Monday night, according to the WJZ report. “This is damage that if you worked in electric distribution at BGE for your entire career, you may see it once.”

A tornado watch issued by the National Weather Service for Baltimore City and neighboring counties expired at 9 p.m. Showers were expected to continue for a few more hours, especially across areas north of Baltimore city, before things started to dry out, according to Austin Mansfield, a meteorologist with the National Weather Service.

Mansfield said there were at least two reports of flooding on Perring Parkway in Baltimore City and that trees and power lines were down in Harford and Carroll counties.

Service on Baltimore’s subway line was suspended temporarily between Mondawmin and Owings Mills “due to the inclement weather conditions in our service area and several trees down blocking the tracks,” the Maryland Transit Administration said in a tweet around 6:30 p.m. As of 9 p.m., storm-related BGE power outages were affecting light rail service serving BWI International Thurgood Marshall Airport.

Inbound flights to BWI were being held until 9:30 p.m. under a ground stop Monday, according to flightaware.com. The airport was reporting departure and arrival delays late Monday.

The National Weather Service cautioned residents earlier Monday to make sure they had a way to receive severe weather alerts as the cold front pushed through the state. Meteorologist Andrew Snyder said then that some areas could see hail the size of a quarter or larger as well as some tornados.

These weather patterns are atypical for August and occur more frequently in the spring, Snyder said.

Portions of the state on Monday climbed to a Level 4 out of 5 risk for severe storms for the first time since June 2013. “It is something that is a bit outside of the norm,” Snyder said.

Temperatures during the day reached the upper 80s to low 90s, but humidity made it feel closer to between 100 and 105 degrees.

Storm conditions developed east of the Blue Ridge Mountains before reaching the Interstate 95 corridor around 6 p.m.

Forecasters had said there was also a chance of damaging wind gusts — and possibly rapidly forming tornadoes. The threat of hail was expected to diminish as the line of storms pushed eastward.

BGE mobilized its Storm Center ahead of the weather and sent mutual assistance resources to BWI at around 1 p.m.

The utility company said it was prepared to respond to service interruptions caused by the storm. Customers were encouraged to prepare ahead of time and to sign up for email and text notifications for updates.

Harford County officials earlier Monday cautioned residents to monitor the government’s Facebook page for updates on any power outages, downed trees or wires. Their offices closed at 3 p.m. Monday to prepare for the potential of “hurricane force winds,” but the emergency operations center was activated to “monitor the situation,” according to Harford County Executive Bob Cassilly.

High pressure was expected to return Tuesday and into Wednesday with breezy conditions. A warm frontal boundary from the south should bring additional showers and thunderstorms Thursday and Friday.

Clara Longo de Freitas contributed to this report.

lillian.reed@thebaltimorebanner.com

More From The Banner

Say goodbye to Howard County’s farm museum. What comes next?

Maryland hospitals stopped suing patients with unpaid bills. Will they start again?

Sea-level rise threatens efforts to dig into Harriet Tubman’s past in Eastern Maryland

Afghan refugees struggle to acclimate to their new home in Baltimore