Avalanche danger in Cascades is high through this weekend
WENATCHEE – A forecast for rain and snow at higher elevations in the Cascade Mountains could also cause dangerous avalanche conditions for mountain travelers, and especially for backcountry skiers, snowmobilers and other winter recreationists.
“A warming trend with rain on top of a lot of snow layers leads to a dangerous profile,” said Dennis D’Amico, a meteorologist for the Northwest Avalanche Center in Seattle.
The avalanche center issued high-danger avalanche warnings for all of the North Cascades and the west slopes of the Central and South Cascades Thursday. A considerable-danger avalanche warning was issued for the east slopes of the Central and South Cascades.
Backcountry travel is not recommended and all avalanche terrain should be avoided for the west slopes or entire North Cascades area north of Lake Chelan.
Dangerous avalanche conditions are also present on the east slopes of the Cascades south of Lake Chelan. “If you venture out, use conservative decision making and slope selection to stay safe,” the avalanche center recommends on its website.
The warnings Thursday included Cascade passes. Snoqualmie Pass was closed in both directions Thursday due to avalanche danger and control work that continued throughout the day. Stevens Pass was open, but chains were required. Tumwater Canyon was closed due to avalanche danger. A detour through Plain was open.
Stevens Pass Ski Area received 10 inches of new snow Wednesday night and Thursday morning. Ski conditions were good, but snow is expected to turn to rain today. Avalanche warnings do not apply to groomed ski runs, but off-trail runs can be dangerous. Three experienced skiers were killed in an avalanche while skiing out of bounds near Stevens Pass Feb. 19, 2012.
The snow level is expected to rise to 7,000 feet Friday, well above mountain passes, wrote Cliff Mass, University of Washington atmospheric science professor and weather blogger.
“During the past several weeks, mountain snow lover have enjoyed a bonanza. More and more snow, with no rain periods. Deep soft snow. No ice. But the good times are over. A warm, wet atmospheric river is upon us. And Cascade Concrete is about to return,” Mass wrote Thursday.
Rain could be heavy in the North Cascades, leading to very dangerous avalanche conditions. Rain and warming weather can gradually stress and load buried weak layers of snow, resulting in large and destructive avalanches, according to the Northwest Avalanche Center.
The center identified specific avalanche danger areas in Icicle Canyon, Scottish Lake High Camp, Rainy Pass near Lake Wenatchee, and Diamond Head near Blewett Pass. A skier on Wedge Mountain was caught and carried in a smaller storm slab avalanche Monday but was not injured.
D’Amico said the dangerous conditions will persist through the weekend. Warmer, wetter weather could settle the layers some over time.
“If they get tested enough, they will avalanche and that solves the problem,” he said. Staff will be out next week to test specific areas for weak layers. The center also relies on reports from ski areas and the public on its observations page: nwac.us/observations.
The snow level is forecast to drop back to 4,000 feet by Friday night, with a gradual cooling trend for the Cascades.