Record heavy precipitation and cooler conditions across Western North America earlier this year have again given way to record warmth as a strong high pressure ridge and associated extreme Pacific and Arctic Ocean surface temperatures have ushered in blazing heat and multiplying wildfires.

In California, massive wildfires have forced nearly 5,000 people to evacuate. In British Columbia, 14,000 have fled as more than 1,000 firefighters battle numerous large blazes. And along coastal Alaska and Canada’s Northwest Territory, large wildfires are burning near the shores of an, until recently frozen, Arctic Ocean.

(Large wildfires spill plumes of smoke over major sections of North America on July 11, 2017. Image source: NASA Worldview.)

In the U.S., the Whittier fire, which forced mandatory evacuations in southern California, is now 48 percent contained after having burned 12,000 acres. In the north of the state, near Oroville, the Alamo fire is 65 percent contained at 28,000 acres and evacuation orders have been lifted.

As large fires continue to burn across the west, the U.S. Interagency Fire Center now has a stated national preparedness level of 4 out of 5 — or the second highest alert rating. So far 2017 has seen 3,593,000 acres burned in the U.S. — which is above the 10 year average. An average that has already been pushed higher due to human-forced warming and an overall lengthening of the fire season.

Further north, British Columbia is suffering a rash of severe fires as extreme heat and high winds are blasting away at vegetation that vigorously regrew when drought conditions retreated earlier this year. Now, 215 active fires are reported as the province mobilizes national military forces and considers making calls for international aid. Presently, 21 large fires are causing considerable havoc throughout BC. Fire officials remain on heightened alert as strong winds, heat, and lightning threaten to make a bad fire situation even worse over the coming days.

Still further north and extending all the way to the shores of the Arctic Ocean, satellite photographs provided by NASA show large wildfires burning through typically frozen regions of Canada’s Northwest Territory and in northern Alaska. Many of these fires are quite vigorous — producing large smoke plumes that have blanked much of the region.

(Fires burning near the Arctic Ocean on July 10, 2017. For reference, bottom edge of frame is 280 miles. Image source: NASA Worldview.)

Such widespread burning over such a large region of North America — extending from California to the Arctic Ocean — has been spurred primarily by record heat building beneath a massive high pressure ridge. In the far North, temperatures approached 90 degrees Fahrenheit just south of the Mackenzie Delta near the Arctic Ocean earlier this week. Over typically cool British Columbia, temperatures have consistently ranged in the 80s and 90s and are expected to continue to hit near the 90 degree mark this week. And in the U.S. Southwest, numerous temperature records were broken over recent days as readings rocketed into the 100s and 110s.

Both the heat and these massive fires have likely been made worse by human caused climate change. Overall, global temperatures have recently hit around 1.2 C above 1880s averages. As a result, over 80 percent of the globe, heatwaves are both more severe and more likely to occur. Meanwhile, due to climate change related factors, the western wildfire season in the U.S. is now 105 days longer than it was in 1970 — just 47 years ago. Arctic sea ice retreat in recent years has likely accompanied further warming of the far northern land masses which have also seen increasingly severe wildfires over permafrost zones.

Links:

Wildfires in Canada, California Force Thousands to Evacuate

BC Wildfire Status — All Eyes on the Weather

Canadian Interagency Fire Center

National Interagency Fire Center

NASA Worldview

Earth Nullschool

Climate Change is Tipping Scales Toward More Wildfires

Unprecedented Climate Extremes

Unprecedented Wildfires Over Canada and Siberia

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