Weathercatch: Why our region was blanketed with smoke a year ago this week

One year ago, wildfire smoke stretched from Seattle to Spokane, clotting the skies with haze that’s rarely seen in mid-October.

“Pacific Northwest endures a hot and smoky October,” blared a New York Times headline. On that Oct. 19 day, “weather stations throughout the Pacific Northwest were recording the worst air quality in the United States, while Portland and Seattle ranked among the worst big cities globally,” the article said.

Smoke and haze covered most of the Inland Northwest as well, with air quality ranging mostly between moderate and unhealthy. Wenatchee, Leavenworth, Newport, Sandpoint and Bonners Ferry were among the cities most affected, where low-level haze muted rolling hills and autumn foliage.

Our region is accustomed to the intrusion of wildfire smoke in summertime, but a week-and-a-half before Halloween? In a typical year, fire season would be winding down or finished by then.

But last autumn was far from typical. Hot, dry weather during September and most of October set the stage for new wildfires to start and existing ones to spread. During the first three weeks of October, temperatures ran about 10 degrees above normal in Washington and North Idaho. Highs in the Inland Northwest ran mostly in the 70s and 80s. On Oct. 16, Seattle soared to 88 degrees, the city’s hottest temperature recorded so late in the season.

At mid-month, 32 wildfires were burning in Idaho, 13 in Washington and nine in Oregon, according to the National Interagency Fire Center based in Boise. As fires burned, breezy conditions sent excessive amounts of smoke into parts of Washington and North Idaho. Then a high pressure system created a stagnant air flow that kept the smoke from dispersing, and we became national news.

Fortunately, a big shift in the weather pattern brought the smoke – and eventually the wildfires – to an end. A storm system moved into the Pacific Northwest on Oct. 21, bringing heavy rains and cooler-than-average temperatures. Consequently, one could say we pretty much bypassed autumn last year, essentially going from summer to winter.

But that’s not the case this autumn. Although we’ve enjoyed plenty of warm, dry days, we’ve also experienced intermittent spells of cool temperatures, breeziness and rounds of rain. Those autumn-like intervals helped suppress late-season wildfires and disperse lingering smoke.

This year’s relatively wildfire-free autumn came on the heels of a combustive August in the Inland Northwest, when two heat- and wind-driven wildfires killed two people and destroyed hundreds of homes near Moses Lake and the tiny town of Elk.

In different ways, 2023 and 2022 illustrate how weather conditions are a curse and a blessing when it comes to wildfire seasons.

Nic Loyd is a meteorologist in Washington state. Linda Weiford is a writer in Moscow, Idaho, who’s also a weather geek.