Title: Alaska’s Changing Environment | IARC
Headings: Alaska's Changing Environment 2019
Alaska's Changing Environment 2019
Documenting Alaska's physical and biological changes through observations
Seasons
Big fire seasons more frequent
Dramatically more smoky days
Storminess not increasing
River break-up happening earlier

Content: ice break-up of Alaska’s big rivers is a sure sign of spring; wildfires are a summer issue, and the season is lengthening; costly coastal flooding along the Bering and Chukchi Seas has historically been an autumn concern. While powerful storms impacting maritime operations near the Aleutians and Gulf of Alaska can occur any time of year, the strongest storms nearly always happen in the fall and winter months. Many of these seasonal events have experienced profound changes in recent years. Big fire seasons more frequent
Warmer springs and earlier snow melt had lengthened the wildfire season to the point in 2006 when Alaska’s interagency fire management organization changed the “start date” for wildfire response from May 1 to April 1. While the year-to-year variability of acreage burned has changed little, the frequency of large wildfire seasons has increased dramatically. Wildfire seasons with more than one million acres (red bars in graph) burned have increased by 50% since 1990, compared to the 1950–1989 period. Dramatically more smoky days
As the frequency of big (1+ million acres) wildfire seasons has increased, so has the frequency of smoky days, posing a significant health hazard. Prior to 2004, Fairbanks had only one summer (1957) in the previous half century when there were more than three weeks of significant smoke.