GNFAC Avalanche Advisory for Wed Jan 1, 2014

Not Current Advisory

Good morning and Happy New Year. This is Mark Staples with the Gallatin National Forest Avalanche 
Advisory issued on Wednesday, January 1 at 7:30 a.m. 

AVALANCHE WARNING

The Gallatin National Forest Avalanche Center is issuing a Backcountry Avalanche Warning for the 
northern Gallatin Range.  Rain and snow has fallen in the northern Gallatin Range with about 7 inches 
of snow. More importantly the equivalent amount of water is nearly an inch of liquid precipitation. 
This precipitation was accompanied by very strong winds. This snow has fallen on a weak and unstable 
snowpack which was producing avalanches prior to this storm. The avalanche danger is rated HIGH on 
all slopes in the northern Gallatin Range.  Very dangerous avalanche conditions exist.  Travel in 
avalanche terrain is not recommended and avalanche run out zones should be avoided.

This warning will either be terminated or updated by 6:30 AM on Thursday, January 2.

Mountain Weather: 

Since yesterday morning the mountains near Bozeman and Big Sky have received 5-7 inches of new snow. 
Areas further south near West Yellowstone and Cooke City received about 4 inches. Some areas received 
a little rain as well. Temperatures dropped overnight and this morning ranged from the mid-teens F 
to 20 degrees F. Winds were blowing 15 mph gusting to 35 mph from the WNW. A little more snow should 
fall this morning but not accumulate. Today temperatures will be in the low 20s F and winds blow 
10-30 mph from the WNW. More snow should come Friday.

Snowpack and Avalanche Discussion: 

Northern Gallatin Range

The amount of snow that has fallen doesn’t matter as much as the snow water equivalent (SWE) of 
yesterday’s precipitation. In Hyalite Canyon the Shower Falls SNOTEL site recorded 0.8 inches of SWE 
with 7 inches of snow. The upper bowls may easily have a foot or more of new snow. Additionally winds 
were blowing 23 mph and gusting to 46 mph this morning on top of Flanders Mountain. Prior to this 
storm the snowpack has given us plenty of warnings in the form of avalanches occurring on Mt Ellis 
and throughout Hyalite Canyon. Some slides occurred on slopes just under 30 degrees in steepness. 
Other slides propagated over very wide areas. For these reasons today the avalanche danger is rated 
HIGH on all slopes.