Friday, May 19, 2023

When will the smoke in Central and Eastern WA clear out?

Smoke from the Canadian wildfires continues to impact Central and Eastern Washington, with monitors observing Air Quality Index values corresponding to Moderate and Unhealthy for Sensitive Group levels.


Due to the residual smoke lingering in the region, the Air Quality Alert has been expanded to include all Central and Eastern Washington counties. The Air Quality Alert will expire tomorrow morning at 10am.

Some haze and smoke will persist throughout today, and temperatures will get hot, but air quality should slowly improve thanks to a push from southwest winds. We'll return to our normal May air quality conditions by the end of the weekend with the arrival of a cold front.  The latest FireWork model forecast animation below shows the smoke plume moving away from Washington State:

Thursday, May 18, 2023

Welcome to the 2023 Wildfire Smoke Season

Wildfire season is starting a bit earlier than expected due to smoke from large fires in central Alberta. While the Canadian fires have been burning for a couple weeks, shifting weather patterns to northeasterly winds brought the smoke to Washington State. This morning's GOES-WEST satellite image shows the plume of smoke across the state. Luckily, that plume of smoke is mostly staying above us--it's too high in the atmosphere to mix down to the surface. 

However, we are seeing some ground-level smoke impacts in the north central and eastern parts of the state, with monitors observing hourly PM2.5 concentrations corresponding to an Air Quality Index of Moderate:

        Source: EPA Fire and smoke map, 8:45am

An Air Quality Alert has been called for the following counties and expires Saturday, May 20 at 10am: Okanogan, Ferry, Stevens, Pend Oreille, Lincoln, Spokane, Adams, and Whitman. PM2.5 levels may reach Unhealthy for Sensitive Group levels in these counties. While today will be hazy in these areas, relief from the smoke will come later in the day with the arrival of southwest winds. If conditions improve, the Air Quality Alerts will be lifted before Saturday.

As far as the rest of the state, the smoke is high enough in the atmosphere and very unlikely to mix down to the surface and impact the air we breathe. Take a look at this image of the smoke aloft from Puget Sound Clean Air Agency's ceilometer in Marysville, where we can see the smoke (dark grey bands) present at around 3-5 km above ground:

Smoke in May caught us all by surprise, but it's a good reminder to be prepared for the upcoming wildfire smoke season. We'll update this blog as conditions change, and be sure to visit the Health Information tab on this page for tips on how to protect yourself from wildfire smoke.