About the only good news was the time - 3:45 a.m. - when few people were in the business district of the Cascades foothills town about 30 miles east of Seattle.
"We are very, very fortunate that it happened in the early morning. If it was two hours later the street would have been very busy," said Josie Williams, public information officer for Eastside Fire and Rescue.
A couple of minor injuries were reported at an assisted living facility where windows were blown out, she said.
It could take days to investigate the cause and estimate the value of the loss, she said.
Another Eastside Fire and Rescue spokesman, Wes Collins, said the blast may have been caused by a natural gas leak at a former pizza restaurant reportedly under renovation.
That building was leveled and the blast and fire also destroyed a barber shop and a separate building with three offices in the strip mall, Williams said. Debris was thrown 200-to-300 feet, blowing out windows and crumpling doors at a gas station and tire store. Flying debris also broke windows at a nearby apartment.
The manager of the gas station was one of the few people awake at the time. The manager heard alarms going off from the building before it exploded and called 911, Williams said.
The blast awakened North Bend residents including three firefighters at the station about two blocks away, Williams said. In all, about 80 firefighters from various departments responded as the fire went to two alarms.
Puget Sound Energy utility workers turned off natural gas and electricity in the area to help firefighters.
Residents told KOMO News that they thought it might have been an earthquake or plane crash as houses rocked enough to knock pictures off walls. One woman said she heard the blast 5 miles away.
A nearby school was able to open as scheduled Friday and residents were allowed back into the area after the fire was out and the area cleared.
"There was a lot of debris all over the road," Williams said. "It was huge. We're so fortunate it was early in the morning and not a couple of hours later."