SANDPOINT — This avalanche season is shaping up to be one of the deadliest in the United States since 1910, according to the Idaho Panhandle Avalanche Center.

"This week starts with a somber reminder of why the avalanche forecast is so important," said Jeff Thompson of the IPAC.

Fifteen people have died in avalanches since the start of the month, the highest number of avalanche deaths recorded in a seven-day period since the U.S. Forest Service's National Avalanche Center began tracking deaths, the center's director Karl Birkeland, told CNN.

Two people were killed in slides in Utah, while a third perished in Alaska. The most recent death occurred in central Washington on Monday, when an off-duty state patrolman was caught in a slide.

Thompson said in an IPAC avalanche forecast that most western snowpacks are experiencing widespread, deep and persistent snowpack instabilities and conditions in the Selkirk and Cabinet mountains, in addition to the Silver Valley, are no exception.

"There have been many reports of big avalanches in the Silver Valley and Selkirk/Cabinets. Skiers and sledders are experiencing propagation over long distances and it’s catching experienced sledders and skiers by surprise," Thompson said in the forecast.

Currently, dangerous avalanche conditions exist in near treeline on all aspects as well as above treeline on leeward slopes, the IPAC advisory said. Cautious route finding and accurate snowpack evaluation are essential.

"Natural avalanches are possible and human triggered avalanches are likely on slopes over 25 degrees. Yes, you heard me right...25 degrees! Basing travel decisions on past experiences (terrain familiarity) can get you in trouble. Safe zones used in the past may not be safe zones right now," Thompson wrote.

Keith Kinnaird can be reached at kkinnaird@bonnercountydailybee.com and followed on Twitter @KeithDailyBee.