A powerful nor’easter wreaked havoc in Wareham on Friday as emergency crews scrambled to keep up with an onslaught of downed trees and electrical wires that cut power to 99 percent of town.

During the height of the storm, a slew of major roads and side streets became impassable, homes and cars were damaged and one on-duty Onset firefighter was seriously injured after being struck by a car.

Late Friday, Eversource reported that 14,184 Wareham customers were without electricity. According to Eversource officials, crews are “working non-stop to repair the destruction caused by the high winds, rain and snow.”

To report a power outage, contact Eversource online at www.eversource.com or call 800-592-2000.

The storm began early Friday morning and had knocked out power to a couple hundred customers by late afternoon. Emergency crews responded to minor calls throughout the day.

At approximately 6 p.m., the wind picked up and heavy rain started, sparking a near non-stop barrage of calls for downed trees, tree limbs and electrical wires. According to emergency broadcasts, numerous homes, mobile homes and cars were damaged by fallen trees and branches. An office building at 379 Main St., home to the former Franconia Fuel, Co., had a large portion of its roof torn off by wind.

Power was out at nearly all traffic lights in town by 10 p.m. and debris had closed portions of Cranberry Highway in East and West Wareham. Parts of Indian Neck Road, Carver Road, Dowd Avenue, Main Avenue and many other streets were closed, too.

In response, Town Administrator Derek Sullivan urged drivers to remain home. He said crews needed space to work safely as widespread power outages and driving rain reduced visibility.

“Drivers are putting themselves, their families and first responders at risk by being on the roads,” said Sullivan. “It’s not safe out there.”

Sullivan said he and public safety officials will survey the damage Saturday morning.

Wareham Week has reached out to fire and police officials for additional information.