Residents are seeing smoke in the sky from the Diamond Creek fire. This aerial photo was taken of the massive fire earlier this month. (image from facebook)

A massive fire that has been burning in the US back country for more than a month has crossed the line into Canada.

BC Wildfire Service says the Diamond Creek fire crossed the border sometime overnight.

“We’re assessing by helicopter this morning. We’re looking at where the fire spread and to see how large it is,” Justine Hunse, fire information officer for BC Wildfire Service, said.

The fire is in the vicinity of Border Lake about 70 kilometers west of Osoyoos or 60 kilometres south west of Keremeos.

“It’s burning in the back country and it is currently not immediately threatening any structures or communities,” Hunse said.

The fire was reported on July 23 by a hiker in the Pasayten Wilderness in Washington State.

Related: Ash falls from the sky, smoke lingers in the Okanagan

As of this morning the fire has grown to almost 20,200 hectares (50,000 acres).

The US Forest Service is reporting that just over 120 hectares (300 acres) of the back country has burned in Canada as of Wednesday morning.

Smoke from WA's largest wildfire expected to hit Winthrop, Twisp, Okanogan, and Omak. See latest https://t.co/Pv7Gw208iO #DiamondCreekFire pic.twitter.com/h1sqmfmaIR — WA Dept of Ecology (@EcologyWA) August 5, 2017

The fire is causing smoke and ash to come into the valley and the Air Quality Health Index rating is currently sitting at three. The smoky skies advisory is still in place.

We will update this story as more details come available.



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Ash rained on the valley last night.