A tree that caught fire during Sunday afternoon storms dropped a burning branch onto power lines on Avalon Drive in Bethesda, triggering a transformer explosion that knocked out electricity to 40 Pepco customers.

Montgomery County Fire and Rescue Service received a call around 5 p.m. Sunday, Aug. 2, from a homeowner who reported a tree had been hit by lightning, according to NBC Washington. When crews arrived on Avalon Drive, they found the tree ablaze.

The burning branch then fell onto overhead wires, causing the transformer to explode and cutting power to surrounding homes, fire officials said. The block went dark.

Diana Blumenfeld, an Avalon Drive resident, saw smoke and flames from her window.

"We lost power and looked outside the window and saw lots of smoke, and there were flames in the street," Blumenfeld told NBC Washington. "And then we could see fire outside our window, and initially it looked like the house two houses down was on fire, but it was actually the tree."

Blumenfeld said firefighters arrived before most neighbors realized what had happened. The rain eventually helped extinguish the blaze, but when the branch broke free and severed the remaining wires, the transformer blew and the rest of the power went out.

Pepco confirmed 40 customers lost service and said repairs were expected by midnight Sunday.

Recurring problem

Blumenfeld said the combination of trees and above-ground wires causes frequent outages on her street and called for the utility to bury its lines underground.

The incident is the latest in a series of storm-related emergencies in Bethesda this summer. Severe storms on Tuesday, July 28, downed trees and wires on Cardigan Road and collapsed a Mobil gas station canopy on Georgia Avenue.

Residents who experience downed wires should stay at least 30 feet away and call 911. Pepco outages can be reported at 877-737-2662 or through the utility's online outage map.