POWELL BUTTE, Ore. -

A fierce fire tore through an outbuilding and sent up thick smoke in Powell Butte Monday afternoon before crews could douse the flames, authorities said.

Crook County Fire and Rescue was dispatched around 3:40 p.m. to the burning outbuilding in the 6200 block of SW Copley Road, said Fire Chief Matt Smith.

An engine crew from the Powell Butte station was on scene within four minutes and found flames venting from the roof, Smith said.

The structure was a complete loss, the fire chief said, adding that the cause was under investigation.

Two structure tenders, two water tenders, a wildland engine, ambulance and 14 firefighters responded to the blaze, which neighbors said caused at least one explosion heard for some distance.

A witness to the fire said the family wasn't home when it broke out but arrived as firefighters were at work.