'Massive' cloud of wildfire smoke arrives in Seattle overnight

A huge mass of smoke from Oregon and California wildfires made its way through Western Washington overnight Thursday, blown in by shifting winds from the southwest.

The National Weather Service in Seattle said air quality would deteriorate to "very unhealthy" along the I-5 corridor by Friday afternoon.

It said smoky conditions were expected Saturday, too, but there could be some relief on Sunday as the onshore flow starts to clear the air.

Air quality in the Seattle area on Friday morning was considered unhealthy for everyone, according to the state Department of Ecology.

"Unhealthy air quality means that everyone, especially sensitive groups, should limit time spent spent outdoors, avoid strenuous activities outdoors, and choose light indoor activities," the Weather Service said in a bulletin.

State officials urged residents to shop for essentials ahead of Friday, and to invest in filtering devices or create box fans. Additionally, they warned that wildfire smoke inhalation could potentially increase one's susceptibility to contracting Covid-19 and other respiratory illnesses.

Symptoms of smoke exposure include coughing, chest pain, irritated sinuses, burning eyes, and fatigue.