WIth over an inch of snow water equivelant equating to 10 to 15 inches of new snow in the mountains of the advisory area, storm slabs of over a foot deep should be your main concern today, if you choose to travel in avalanche terrain.
Due to the west southwest winds, wind slabs will be found in terrain that is not sheltered from the wind. Due to moderate to extreme winds throughout the day today, wind slabs will be found lower on the slope than normally expected. Even though you are mid slope you should still be on the lookout for wind slabs today and into the weekend.
The PAC advisory area caught the northern edge of this most recent storm, and subsequent dangerous avalanche conditions can be found in the mountains around McCall. However, reports from just south and east of the advisory area showing more signs of instability. This weaker snowpack, coupled with higher snow totals overnight, warrant extreme caution if you are traveling in avalanche terrain south of the advisory area. Sawtooth Avalanche Center issued an Avalanche Warning last night that will last for 24 hours due to persistent weak layers in the snowpack, high winds, and high snowfall totals. Expect the avalanche danger within the Sawtooth Avalanche Centers' advisory area to be EXTREME today. This means that natural and human caused avalanches are certain.
While we DO have persistent grain types in our snowpack that could prove to cause avalanches, currently they are not our top concern. That being said, now is NOT the time to be pushing your luck in the mountains. Dangerous conditions do exist if traveling in, below, or on slopes connected to avalanche terrain.
Be sure everyone in your group has at a minimum a beacon, probe, and shovel and knows how to perform a companion rescue.
We toured up Granite Mountain yesterday to look at how recent storms have affected the snowpack of the upper elevation on north and northeast facing terrain. We saw no evidence of natural activity, however, the results from our snowpack tests showed some possibilties of avalanches initiating at density changes throughout the snowpack. These density changes were the product of previous storms and wind activity. We did find two melt freeze crusts deep in the pack on north facing terrain. These crusts had surgary snow that also caused initiation under the stress of a compression test.
We have had reports from both the Lick Creek Summit area, and east of Landmark, of collapsing in the snowpack or 'whoomping'. This is a red flag for instabilities in the snowpack.
Precipitation will continue across the advisory area today with total accumulations around 3-6 inches. Winds out of the west southwest will blow between 20-30mph with gusts up to 45mph. Showers associated with this warm front will weaken through Friday afternoon as an assault of arctic air moves into the state. This weekend looks to be a cold one.
This avalanche advisory is provided through a partnership between the Payette National Forest and the Payette Avalanche Center. This advisory covers the West Central Mountains between Hard Butte on the north and Council Mountain on the south. This advisory applies only to backcountry areas outside established ski area boundaries. This advisory describes general avalanche conditions and local variations always occur. This advisory expires at midnight on the posted day unless otherwise noted. The information in this advisory is provided by the USDA Forest Service who is solely responsible for its content.