Easton, WA – A propane leak may be to blame for an explosion in Kittitas County that destroyed a 3,000-square-foot house, firefighters said.

A fire spread quickly through the three-story house on Kachess Lake after the blast late Saturday night.

The owners of the house weren’t home at the time. Neighbors a half-mile away heard the boom, KIRO 7 Eyewitness News reported.

Firefighters were forced to fight the flames from a safe distance down the snowy hill.

Firefighters said it appeared that propane gas filled the home on Saturday night and a furnace might have triggered the blast.