Archived Advisory for Wed Apr 2 2008

Audio- listen online, right now

Podcast- listen on your iPod

Subscribe- to the daily Email

2 April 2008

Good morning. This is Ron Johnson with the Gallatin National Forest Avalanche Advisory issued on Wednesday, April 2, at 7:30 a.m. Bridger Bowl Ski Area, in partnership with the Friends of the Avalanche Center, sponsor today’s advisory. This advisory does not apply to operating ski areas.

MOUNTAIN WEATHER

Yesterday the Bridger Range got 3-4 inches of new snow. An inch or less dusted the mountains around Big Sky, West Yellowstone and Cooke City. During the afternoon westerly ridgetop winds blew 15-30 mph. This morning they’ve subsided to 10-20 mph. There is enough moisture and instability in the atmosphere over southwest Montana that snow showers will occur this afternoon and evening. Snow accumulations will be 1-3 inches. Mountain temperatures will warm to the 20’s F and westerly ridgetop winds will remain 10-20 mph.

SNOWPACK AND AVALANCHE DISCUSSION

The Bridger and northern Gallatin and northern Madison Ranges:

Yesterday, the few inches of snow that accumulated on Monday produced a few small avalanches at Bridger Bowl when ski patrollers used explosives on steep slopes. Karl Birkeland and his partner skied on Saddle Peak and found stable snow; however, on southerly aspects a couple of thin ice crusts surround by small faceted crystals buried 1.5 – 2 feet deep produced clean shears. Last weekend two human triggered avalanches occurred in the Bridger Range. They most likely fractured on layers similar to those Karl found yesterday. Yesterday ski patrollers at Big Sky ski cut a few small wind slabs; otherwise they reported good skiing on stable snow. Yesterday afternoon I noticed snow plumes streaming off the Bridger Range. Today, recently formed wind slabs could fracture under skis, snowboards and snowmobiles and a MODERATE avalanche danger exists on wind-loaded slopes steeper than 35 degrees. All other slopes have a LOW avalanche danger. Regardless of the avalanche danger, remember to ask this simple question before riding or sliding on any steep slope: “What will happen to me if an avalanche occurs on this slope?” If you don’t like the answer, go ply your craft elsewhere.

The southern Madison and southern Gallatin Ranges, the Lionhead area near West Yellowstone, the mountains around Cooke City, and the Washburn Range:

Yesterday Doug Chabot and his Swiss colleague were snowmobiling on Lionhead near West Yellowstone. They didn’t see any recent avalanches or notice any snow collapsing or cracking around their snowmobiles. They did find a thin layer of faceted crystals that we’ve been monitoring for 6 weeks. It’s buried 3 feet deep and continues to produce clear shears. A photo of this layer is at:

http://www.mtavalanche.com/photos/photos.php

You can see a video clip of Doug describing this layer at:

http://www.youtube.com/watch?v=J-8UTJR_K8k

A similar layer exists in the mountains around Cooke City. Today a MODERATE avalanche danger exists on all slopes steeper than 35 degrees. Less steep slopes have a LOW danger.

I will issue the next advisory tomorrow morning at 7:30 a.m. If you get out in the backcountry let us know what you found. You can reach us at 587-6984 or email us at mtavalanche@gmail.com

LAST ADVISORY

Our 126th and last avalanche advisory of the season will be issued next Sunday, April 6th.