GNFAC Avalanche Advisory for Fri Feb 5, 2010

Not the Current Advisory

Good Morning. This is Mark Staples with the Gallatin National Forest Avalanche Advisory issued on Friday, February 5, at 7:30 a.m.  Montana Ale Works in cooperation with the Friends of the Avalanche Center, sponsor today's advisory.  This advisory does not apply to operating ski areas.


Mountain Weather

Yesterday, most areas received a meager 1 inch of snow.  This morning with temperatures in the mid teens F, winds increased near Big Sky and were blowing 10-20 mph from the southwest while blowing 5-10 mph everywhere else.  Today's weather shouldn't be too exciting even though satellite images show an approaching area of low pressure.  A weak upper level ridge over southwest Montana will limit any precipitation today.  By tomorrow another inch or two of snow will accumulate mostly in the southern half of the advisory area.  Today temperatures will reach the mid 20's F with light southwest winds blowing 10-15 mph.


Snowpack and Avalanche Discussion

The southern Madison Range, southern Gallatin Range and the Lionhead area near West Yellowstone:

The mountains near West Yellowstone and the southern Madison and Gallatin Ranges contain the weakest snow in the advisory area.  Faceted crystals exist near the ground in all areas, and a layer of surface hoar exists on isolated slopes.  Near Hebgen Lake a large recent avalanche started on the surface hoar layer but stepped down to facets at the ground.  Finding this surface hoar is generally easy in snowpits where it appears as a noticeable stripe in the snowpit wall.  Without digging into the snow, knowing where it exists is difficult but likely locations are sheltered slopes below treeline.

Faceted snow near the ground formed in early December and continues to plague the snowpack.  These facets take such a long time to gain strength that they will likely cause concern for the rest of the season.  Triggering an avalanche becomes a bit more difficult with each passing day and it might take the second, third, or fourth person on a slope to trigger one.  As seen in recent avalanche accidents and fatalities, tracks on a slope do not indicate stability.  For today a CONSIDERABLE avalanche danger exists on slopes steeper than 35 degrees.  Less steep slopes have a MODERATE avalanche danger.

Bridger, northern Madison, and northern Gallatin Ranges, mountains around Cooke City and the Washburn Range: 

Yesterday Eric and his partner went to Cooke City where they found plentiful powder, a deep snowpack, and improved stability.  As he described what he found, I focused on the good news and scared myself when I realized how much I wanted to forget about lurking weaknesses in the snowpack and only see signs of stability.  This is a dangerous mentality knowing that facets near the ground produced the most widespread avalanche cycle in over 20 years just 4 weeks ago.  Similar conditions exist near Bozeman and Big Sky where stable slopes can be found, but faceted snow near the ground can still produce an avalanche especially if you find an area with shallow snow.  Today search for signs of instability because human triggered avalanches are possible and the avalanche danger is rated MODERATE.

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


Mark your calendars: Montana Ale Works is hosting a benefit dinner for the Friends of the Avalanche Center on Monday evening, February 8th.  Chef Roth Jordan has assembled an amazing five course menu themed "Mountains of the World" with foods from Chile, Montana, France, New Zealand and Germany.  Dinner is limited to 40 seats with the first course served at 6:30 p.m.  Tickets to this event are $75, all inclusive, and available at Montana Ale Works.  More information is available on our calendar or by calling 587-7700.


The 8th Annual King and Queen of the Ridge will be held at Bridger Bowl on Saturday, February 13th.  ALL proceeds go to the Friends of the Avalanche Center who use the money to promote avalanche education in southwest Montana.  Last winter we taught 62 classes reaching over 4,300 people.  You can help raise money to continue this education in 2 ways:

1). Get pledges and hike the ridge.  You don't have to do 20 laps - you can get flat pledges and hike just once!  Or you can test your mettle and try and break John Yarington's record of 27 laps in 5 hours. 

2). Sponsor someone.  If you don't have someone to sponsor, consider sponsoring Mark, Eric or Doug since we'll be hiking for dollars. 

You can go to  for more information and registration forms.

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