Massive fires rage in Pacific Northwest and Canada, sending smoke south (2024)

Several massive blazes covering at least 100,000 acres are burning in Oregon and western Canada.

With the smoke from the fires infiltrating the Rockies, air quality alerts were in effect Wednesday morning in most of eastern Colorado, including Denver; northern Wyoming, including Yellowstone National Park; and eastern Oregon. Much of western Canada is also under air quality alerts. Some smoke has even spread into the Midwest.

Both Denver and Chicago have ranked among the top 10 most polluted large cities in the world since Tuesday, according to IQAir.com.

Scorching temperatures have helped fuel the rapidly spreading fires. Temperatures have topped 100 degrees as far north as southern Canada, while California and other parts of the western United States are enduring their hottest 30-day stretch on record. Boise, Idaho, has reached at least 99 degrees on a record 16 straight days.

The current fire situation

Because of the number of fires and their size, both the United States and Canada have raised their scales signaling the need for firefighting resources to Level 5 out of 5. In Canada, international crews from New Zealand and Australia have arrived to assist.

As of Wednesday morning, 69 large wildfires were burning in the United States, according to the National Interagency Fire Center.

“Many wildfires in the Northwest area continue to have active to extreme fire behavior, with evacuation orders in effect on 15 fires,” the center wrote in a recent update. “Evacuation orders are also in effect for several fires in California, the Northern Rockies and the Great Basin.”

In Canada, hundreds of fires have started in recent days.

“National mobilization is heavily committed and increased measures need to be taken to support agencies,” the Canadian Interagency Forest Fire Center wrote in its latest situation report.

The center warned that the potential for more fires is “high to extreme.”

Large and notable fires

Some of the worst fires in western North America have been in Oregon, where a lengthy state of emergency was issued earlier in the month for the “risk of catastrophic wildfires.” The state is currently home to 31 large fires and the five largest in the Lower 48 states, ranging from 53,000 to nearly 240,000 acres as of late Tuesday.

“Never seen 31 ‘large’ fires burning in Oregon at once and I’ve been doing this for three decades!” Mark Nelsen, a meteorologist for Portland affiliate KPTV, posted on social media.

Only about a week old, the Durkee Fire in far-eastern Oregon was started by lightning and has rapidly consumed 240,000 acres. While it has mainly affected rural areas, some locations have been evacuated around the fire’s perimeter.

The nearby Cow Valley Fire has also burned more than 133,000 acres.

“This is really shaping up to be a monster fire year across the Pacific Northwest,” U.S. Forest Service spokeswoman Holly Krake told Oregon Public Radio.

To the south, California’s Lake Fire, which began north of Santa Barbara on July 5, has torched about 40,000 acres but recently came under nearly full containment, and evacuation orders have been lifted. A smaller blaze, started by fireworks Sunday, ran through a Riverside neighborhood in Southern California, burning down half a dozen homes.

In western Canada, amid hundreds of wildfires burning, about 25,000 people were evacuated around Jasper National Park on Tuesday. While a majority of the blazes are in British Columbia and Alberta, significant fire activity is also occurring across central to northern Saskatchewan.

Smoke-filled skies

The footprint of wildfire smoke over North America is quite substantial, spreading as far south as Mexico. In most spots, the smoke is at high altitudes and not close enough to the ground to affect air quality.

However, the smoke is affecting air quality near the source of the fires and where atmospheric steering currents direct it.

Across western Canada, the unhealthiest air is over the largely wilderness zone between Fort McMurray and Yellowknife. Poor air quality has also been a frequent issue in Edmonton, Calgary, Saskatoon and Regina.

In the north-central United States, the smoke has caused the air quality index to reach Code Orange to even Code Red levels. Code Orange levels are considered unhealthy for sensitive groups, while Code Red is unhealthy for everyone.

Parts of North Dakota had Code Red levels Tuesday, while much of the area from the High Plains toward Colorado witnessed Code Orange.

While much of the smoke in North America is from Canada, fires in the Pacific Northwest and California are also contributing. Parts of eastern Oregon reached Code Purple levels for very unhealthy air early Wednesday.

How this year compares to the past

The 3.5 million acres burned by fires in the United States so far this year is about four times the area burned last year at this time but is around the average area over the last decade. California’s acreage burned is about twice the norm to date.

Canada’s 5.7 million acres burned have already surpassed the nation’s annual average, following the record-setting season last year, when just shy of 43 million acres were lost. While this year’s activity pales in comparison to last year’s, the number of acres burned is already higher than in 11 of the last 20 years.

Any relief ahead?

Weather conducive to fires is expect to persist through at least Thursday in the Western United States, where high temperatures could reach at least 100 to 105 degrees, threatening records in some cases. On Wednesday, the fire threat is “critical” from eastern Oregon to southwestern Montana, according to the National Weather Service. Dry thunderstorms, producing lightning but little rain, could ignite new fires.

After Friday, the Weather Service says, “the overall fire threat should lessen a bit.”

In the longer term, weather outlooks suggest the fire risk will be above normal through at least September.

In western Canada, conditions are improving somewhat as the heat has eased. A period of cooler and wetter weather could set up late this week and into next week, especially in northwestern Canada.

The long-range outlook calls for a high to extreme risk of high fire activity in southwestern Canada through September, with somewhat lower risks to the north.

Jason Samenow contributed to this report.