GNFAC Avalanche Advisory for Mon Apr 13, 2015

Not the Current Forecast

Good morning. This is Eric Knoff with the Gallatin National Forest Avalanche Advisory issued on Monday, April 13th, at 7:30 a.m. Montana Ale Works in partnership with the Friends of the Avalanche Center sponsors today’s advisory. This advisory does not apply to operating ski areas.

                                                        Avalanche Fatality

The GNFAC is saddened to report that a skier died in an avalanche on the north side of Beehive Peak in the northern Madison Range this past Saturday. He was in a group of four skiing a couloir known as the Hanging Garden. He was the first skier to descend into the middle portion of the couloir where he triggered a very small avalanche that swept him over cliffs. He died of trauma. They were an experienced group who all had avalanche training. The victim was a very conservative decision maker in terms of avalanches. The avalanche was a small wind slab that broke up to a foot deep and was at most 20 feet wide. They had not seen any signs of instability and to their best knowledge the couloir appeared to be free of any wind affected or wind deposited snow. We will complete a detailed accident report which will be available in the next few days. Our sincere condolences go out to the victim’s family and friends (photos).

Mountain Weather

Overnight a trace of new snow fell in the mountains around Big Sky. This morning, temperatures range from the upper teens to mid-20s F under mostly clear skies and winds are blowing 10-20 mph out of the west. Today, high pressure will dominate the weather pattern producing mostly sunny skies and warmer temperatures. Highs will warm into the upper 30s to mid-40s F and winds will continue to blow 10-20 mph out of the W-SW. The ridge of high pressure begins to break down this evening as a storm approaches from the west. Tomorrow looks to be mostly cloudy with a chance of valley rain and mountain snow by the afternoon. 3-6” of snow will likely accumulate in the mountains by Wednesday morning.

Snowpack and Avalanche Discussion

Bridger Range  Gallatin Range  Madison Range 

Lionhead area near West Yellowstone  Cooke City

Yesterday, Mark and I attempted to reach the site of the avalanche fatality that occurred Saturday on Beehive Peak. We were unable to reach the location due to strong winds and heavy wind loading. Mark and Doug will attempt to reach the site today.

Wind slabs continue to be our main avalanche problem. This hazard is confined to upper elevation slopes, primarily those leeward to west, southwest winds. However, swirling winds have potential to load slopes on all aspects. Watch out for textured snow that looks wavy or drifted. Avoid these areas, especially on slopes steeper than 35 degrees.

A secondary avalanche problem today will be loose, wet avalanches. The new snow that fell over the past few days is sitting on a firm ice crust, which will make for a slick sliding surface once the new snow heats up and loses strength. Warming will start on south and east facing slopes, then move towards west and potentially north aspects by afternoon. Pay attention to obvious signs of instability such as small point releases or roller balls and move to shadier aspects if these signs are present.

Today, human triggered avalanches are possible on wind loaded slopes and slopes steeper than 35 degrees which have a MODERATE avalanche danger. All other slopes have LOW avalanche danger.    

We will issue a completed accident report and our final advisory on Wednesday. If you have any snowpack or avalanche observations drop us a line at or call us at 587-6984.