UPDATE — Wednesday, 7 p.m.:
BC Parks has shut down Cathedral Provincial Park southwest of Keremeos due to safety concerns as the Diamond Creek wildfire expanded rapidly into a blaze with rank four and five fire behaviour on Wednesday.
Rank four and five fire behaviour describes a fast-moving blaze that can move through forest like a storm.
The fire crossed the U.S. border aggressively overnight and into the day, according to the B.C. Wildfire Service.
The blaze is within 20 km of Cathedral Provincial Park’s western boundary, though it’s not burning within the park itself.
It has now scorched more than 1,700 hectares of B.C. forest directly south of Princeton and is currently burning 17 km east of the Highway 3 community of Eastgate.
A massive wildfire raging south of the U.S. border in Washington State crossed into Canada overnight.
The BC Wildfire Service said the Diamond Creek fire is burning 70 kilometres west of Osoyoos within the vicinity of Border Lake.
Fire Information Officer Justine Hunse said the blaze burning in rugged terrain and no structures or homes are threatened at this time.
The 19,798-hectare (48,924-acre) wildfire has been burning in the Methow Valley Ranger District on the Okanogan-Wenatchee National Forest for more than a month.
That’s 12 miles north of Mazama, Wash.
The Diamond Creek fire is believed to be the reason why heavy smoke and ash is currently blanketing many parts of the Okanagan Valley.
The aggressive fire grew by more than 6,500 hectares overnight.
Hunse said the fire has burned 1700 hectares of Canadian forest Wednesday.
One structure has been lost and one damaged in the U.S. so far.
B.C. forestry crews are now assisting because it has moved into Canadian territory.
Hunse said they have been communicating regularly with U.S. firefighting officials since the fire was discovered in late July.
B.C. forestry crews have been involved in several flights over the area to monitor and assess the threat to Canada.
Crews surveyed the fire from the air on Wednesday to determine next steps.
“We’re still trying to assess values in the area,” Hunse said, who said the operations team is developing a strategy for the Diamond Creek Wildfire now that it has crossed the border.
Value is described by the B.C. Wildfire Service as, “the specific or collective set of natural resources and man-made improvements/ developments that have measurable or intrinsic worth and that could of may be destroyed or otherwise altered by fire in any given area.”
The Ministry of Environment has issued a smokey skies bulletin covering much of the B.C. Interior.
The public is asked to avoid strenuous outdoor activities and to report to a health care provider if they experience difficulty breathing, chest pain or discomfort.
The air quality index pegs the south, central and north Okanagan at a 5 out of 10, which is considered a moderate health risk.
WATCH: More concern for battle against B.C. wildfires as many seasonal firefighters pulling out and heading back to school