SPOKANE, Wash. -

Fire threatened homes in northwest Spokane County Monday, and sent smoke into the sky that could be seen for miles. It started near north Dover Road and Bluebird Lane.

"There were (six) structures threatened so, what we were trying to do is put handline around the fire," Department of Natural Resources Spokesman Matt Ugaldea said.

The fire sparked around 3 p.m. Monday and Firefighters don't know how it started yet. Crews worked quickly to bulldoze fire lines around it. Two planes and two helicopters flew for hours, dropping water and flame retardant from above.

"We use air resources and dump water and slow the spread and try to limit the amount of acres that were burned," Ugaldea said.

Six homes and outbuildings were threatened at one point, but thanks to crews from Newman Lake to Medical Lake, none of them were damaged. Firefighters say with the hot dry weather we've had, it could have been much worse.

"Any sort of an ignition source or ignition point has the potential for fairly rapid fire spread and growth," Ugaldea said.

Many neighbors were outside their homes watching the fire's progress. Darren Enquist heard about the fire driving home from work.

"First thing I did was hook up my horse trailer to evacuate if we had to," Darren Enquist said.

The Department of Natural Resources says it's largest fire in Spokane County this year. Enquist is glad it didn't spread more.

"I'm relieved, they've done a wonderful job. These guys are out here working real hard and the planes and the helicopters, they've done a wonderful job," Darren Enquist said.

There are still around 70 firefighters at the scene. Many will remain there overnight. The fire is 50 percent contained.