8:30 AM THURSDAY UPDATE:
With wildfire smoke trapped in the Anchorage Bowl on Thursday morning, the Anchorage School District recommended that all schools hold outdoor activities inside, including recess, field days, PE, and outdoor field trips, wrote spokesperson Heidi Embley.
The city’s 100 schools will experience varying conditions and the decision would be made by each school’s principal, she wrote.
A decision regarding after-school activities would be made later Thursday, Embley wrote, but they were expected to be held as the smoke was forecast to dissipate.
Visibility at Ted Stevens Anchorage International Airport was 1.5 miles Thursday morning, according to the National Weather Service.
A temperature inversion could cause smoke from wildfires to become trapped in the Anchorage Bowl through the Memorial Day weekend as air flow shifts and begins blowing from the south, forecasters said.
As crews battled two wildfires in Southcentral Alaska on Wednesday morning -- one near Tyonek and another south of Soldotna -- an inversion trapped smoke in the Anchorage Bowl, causing air quality to drop to "moderate" for several hours, said Matt Stichick, environmental engineer with the Anchorage air quality program.
The Anchorage Health Department received reports that visibility dropped under five miles on the Hillside, Stichick said, and the Anchorage Police Department said it received dozens of calls about the smoke.
As the day heated up, breaking cloud cover and causing the smoke to dissipate, air quality returned to a "solid good" rating, Stichick said.
A similar temperature inversion was expected overnight Wednesday in Anchorage, said David Kramer, a meteorologist with the National Weather Service. Winds from the west overnight were expected, and smoke "may get squeezed under the inversion" Thursday morning, he said. The possible extent of that smoke was difficult to gauge, he said. If smoke did linger in the Anchorage Bowl, it was expected to lift by the afternoon.
The Alaska Department of Environmental Conservation Division of Air Quality issued an air quality advisory for smoke in Anchorage Bowl on Wednesday, in place until Thursday at 4 p.m. An air quality advisory was issued Tuesday for the Kenai Peninsula; it is also in place until Thursday at 4 p.m.
An Anchorage burn ban was in place both Wednesday and Thursday, said John Fee, forester with the Anchorage Fire Department. "The only thing we're permitting at this time is covered barbecue grills and fish smokers," he said.
On Thursday morning, a westerly flow was forecast in Anchorage, then shifting to light, variable winds in the afternoon, Kramer said. Northerly winds were expected Friday morning, with a shift toward light, variable winds by evening.
Over the weekend, a southerly flow was forecast in Anchorage during daylight hours. That airflow may push smoke from the Funny River fire up into the city, Stichick said. Conditions were still uncertain, but "it could very well get smoky," he said.
"I don't think we're quite in the clear yet," Stichick said.
No rain was expected through the weekend, according to Kramer.
Reach Laurel Andrews at email@example.com.
By LAUREL ANDREWS