Good morning. This is Eric Knoff with the Gallatin National Forest Avalanche Advisory issued on Monday, March 28, at 7:30 a.m. Yellowstone Club Community Foundation, in cooperation with the Friends of the Avalanche Center, sponsors today’s advisory. This advisory does not apply to operating ski areas.
Over the past 24 hours the Bridger Range picked up over a foot of snow. The mountains around Big Sky, West Yellowstone and Cooke City picked up 4-6 inches and the northern Gallatin Range received 1-2 inches. Currently, mountain temperatures are in the mid teens to low 20s F and ridgetop winds are blowing out of the W at 5-15 mph. Today, temperatures will warm into the 30’s F and winds will stay light out of the W at 5-15 mph. Skies will stay mostly cloudy through the morning hours, but will begin to clear by late afternoon. A weak ridge of high pressure will produce calm and clear conditions tonight, but another storm is scheduled to impact our area starting tomorrow afternoon.
The Bridger Range:
Surprise - Surprise! The Bridger Range got hammered again. The foot of snow that fell overnight totaled close to one inch of water. This is a heavy load in a short period of time. Despite a fast and heavy load, there are a few factors working in our favor. One – this latest storm came in with very little wind. Two – the snowpack in the Bridger Range is strong and should have no problem supporting the new load.
Today’s primary avalanche concern will be new snow instabilities. Since the new snow fell on a variety of old surfaces, it may bond well to some slopes but not to others. On steeper slopes, fast moving sluffs could potentially push a skier or rider into trees, rocks or over cliffs. Although the winds have not been strong, there is the possibility of finding fresh wind slabs near the ridgelines. Avoiding wind loaded slopes and slopes steeper than 35 degrees will be the best way to avoid being caught in a slide.
Today – human triggered avalanches are likely on wind loaded slopes and slopes steeper than 35 degrees where the avalanche danger is rated CONSIDERABLE. Less steep slopes without a wind load have a MODERATE avalanche danger.
The northern Madison Range, the southern Gallatin Range, the Lionhead area near West Yellowstone, the mountains around Cooke City and the Washburn Range:
The mountains around West Yellowstone, Cooke City and Big Sky did not receive a foot of snow overnight, but they have received 6-8 inches of snow over the past few days. Small incremental loads have not put a tremendous amount of stress on the snowpack, but they have made snow available for wind transport. Although winds have not been cranking, they have been strong enough to move snow onto the leeward sides of exposed terrain features. Yesterday, a skier near Cooke City reported fresh slab development on upper elevation slopes. With winds blowing predominantly out of the south-southwest, upper elevation slopes with a north and east aspect will be the most likely areas to find fresh wind slabs.
Today, snow and wind will make human triggered avalanches possible on wind loaded slopes where the avalanche danger is rated MODERATE. Slopes that have not received a wind load have a LOW avalanche danger.
The northern Gallatin Range:
Over the past 48 hours only 1-2 inches of snow has fallen in the northern Gallatin Range. The lack of snow and wind will likely keep avalanche activity to a minimum.
Today, generally safe avalanche conditions exist. Human triggered avalanches are unlikely but not impossible and the avalanche danger is rated LOW.
Doug will issue the next advisory tomorrow morning at 7:30 a.m. If you have any snowpack or avalanche observations, drop us a line at mtavalanche@gmail.com or call us at 587-6984.
Ride in honor of Steve Green
Next weekend on Saturday, April 2nd, ride Buck Creek Ridge in honor of Steve Green who died in an avalanche last April in McAtee Basin. Meet at 9:30 a.m. at the Buck Creek parking lot near the Corral.