HAGERSTOWN, Md. – Maryland State Police are calling her a hero — and lucky to be alive.

A critical-care nurse who stopped to help at a pre-dawn crash scene on an interstate highway bridge thought she’d be crossing a median when she jumped over a concrete barrier.

Instead, she found herself airborne, plunging at least 100 feet into the river below.

Angela M. Weir, 47, of New Market, was pulled from the Monocacy River by emergency responders and flown to the University of Maryland Medical System shock trauma unit in Baltimore, where she works. She complained of some back pain, but was discharged within a few hours.

Weir had no broken bones, her brother William Floria said in a telephone interview. He said he’s not surprised that she stopped to help after she and her husband, driving east on Interstate 70, saw a dump truck and a tractor-trailer wrecked in the westbound lanes.

“That’s exactly within her character,” he said. “She probably didn’t even think about how safe it would be to go over there. Knowing her, she probably just jumped into action to go help them.”

State police spokesman Greg Shipley said many people with medical training feel an ethical duty to help when they see a need.

“As far as the state police go, we call her nothing less than a hero today for her willingness to stop and help, and we’re very grateful she survived,” Shipley said.

Hospital spokeswoman Karen Lancaster called Weir a fabulous nurse.

“She exemplifies the highest qualities of nursing and selflessness, and we are so proud to call her one of our own,” she said.

State Police Lt. Wayne Wachsmuth said the tractor-trailer, hauling asphalt at about 4:50 a.m., struck the rear of the dump truck, which witnesses said was travelling without lights in the pre-dawn darkness near Frederick, about 40 miles west of Baltimore.

The dump truck driver, Charles H. Williams, 53, of Baltimore, was in serious condition at the Baltimore hospital, Lancaster said.

Wachsmuth said the tractor-trailer driver was taken to a Hagerstown hospital with non-life-threatening injuries.