Good morning. This is Doug Chabot with the Gallatin National Forest Avalanche Advisory issued on 
Wednesday, February 22 at 7:30 a.m.

Mountain Weather: 

During the last 24 hours snow fell, winds blew and temperatures warmed.  Since yesterday morning 
the mountains got 4 to 10 inches of new snow with varying densities.  Cooke City has about 10 inches 
(1.4” SWE).  Higher elevations were colder than the measuring stations.  Colder air makes lower 
density powder with the same water equivalency, so expect substantially more snow the higher you 
go.  Winds are blowing out of the west at 30-60 mph with mountain temperatures in the mid to 
high 20s.  The storm will continue today and drop another 6-10 inches in the mountains (.6-.8” SWE) 
with strong winds and falling temperatures.

Snowpack and Avalanche Discussion: 

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

Lots of heavy, wet snow fell with stiff westerly winds.  Faceted snow formed at the surface during 
last week’s clear weather and is now buried.  Skiers triggered slides on this layer over the weekend 
and it will continue to avalanche as more snow is piled on top of it (Sunday’s video and photo shows 
this).  Compounding the danger is weak, sugary, faceted snow at the ground.  Avalanches breaking in 
the upper layer may step down to the ground creating large, deadly slides. Storm totals 
measure 8- 12 inches, but inches of snow are not important; its total weight is.  And the snow 
weighs a lot: 1.5-1.8” of SWE. Strong wind gusts to 60 mph have created thick, meaty drifts which 
further raise the instability.

The avalanche danger is rated HIGH on:

    * Any wind loaded slope.
    * Any slope 35 degrees or steeper.

The avalanche danger is rated CONSIDERABLE on all other slopes.  This danger rating is very close 
to our Warning criteria.  If snow continues to fall the danger will also increase.

I recommend riding lifts in the ski areas, sticking to groomed trails or staying home.  If you do 
head into the backcountry, make sure your inclinometer is handy.  Slopes steeper than 30 degrees 
are avalanche terrain.  Do not travel in or underneath these slopes, no matter how small they are.

Mark will issue the next advisory tomorrow morning at 7:30 a.m.