Okanogan Complex fire the largest in Washington state history

The massive Okanogan Complex of wildfires were measured overnight at just over 1,000 square kilometres, with smoke impacting some B.C. communities.

Smoke from the massive fire has led to smoke advisories across B.C.

Brandon Gardner, a firefighter with Snohomish County Fire District 7, pulls a water hose into position while helping prevent a wildfire from spreading to a homeowner's property near Okanogan, Wash. (Ian Terry /The Herald/Associated Press)

A massive fire burning in north-central Washington is now the largest in the state's history, and is impacting communities in B.C.

The massive Okanogan Complex of wildfires were measured overnight at just over 1,000 square kilometres, said Washington state fire spokesman Rick Isaacson on Monday.

The fires grew by more than 67 square kilometres on Sunday and are expected to spread even more in coming days.

Smoke from the fires could be seen from across southern British Columbia, prompting a smoky skies advisory for most of the region.

The wildfires are slightly bigger than the Carlton fires of 2014, which also burned in Okanogan County and destroyed an estimated 300 homes.

Isaacson warned the fire could burn for several more months. Officials are still trying to determine how many homes and other structures have been destroyed.

About 1,250 people are battling the fires. Last week, three firefighters were killed and four injured near Twisp, Wash.

Another set of fires in Washington state, called the Kettle Complex, was threatening the southern B.C. communities of Grand Forks and Christina Lake late last week.

That fire, last estimated at 190 square kilometres and only 15 per cent contained, is about five kilometres south of the Canadian border.

B.C. Wildfire Services has sent in firefighting crews to help battle the fires.

(The Okanogan region in Washington state uses a different spelling than the Okanagan region of B.C. The name derives from the Okanagan language place name ukʷnaqín.)

With files from CBC News