The fire sent a mother running to safety with her two children and destroyed three cars and a carport.
As a smoke column visible across much of the Interbay and Lake Union areas lifted into the sky, firefighters rushed to the garage in the 2800 block of 22nd Ave. W. and began dousing the flames.
Moments later, firefighters said they had the flames under control and no one was hurt.
The fire torched three cars, turned the carport to ash in some places, scorched a few nearby fences, and nearly spread to a tri-plex. That's where Beth Young was sleeping with her 2-year-old and 8-month-old children. She had one in each arm as she ran out of the house into the smoke.
"We just basically had to get out as fast as possible," Young said. "It's horrible to maybe think your whole house is going to go up in flames."
Seattle Fire spokesman Kyle Moore said they don't know what yet what sparked the blaze, but they have called in the Seattle Police arson bomb squad to assist in the investigation.
Neighbors told officers there might have been a teenager playing with fire near the cars. Several hours after the fire was put out, police announced they had arrested a 12-year-old boy.