Avalanche Warning Issued by Gallatin National Forest Avalanche Center
Provided by Billings office of the National Weather Service (part of NOAA)
An Avalanche Warning has been issued through at least 6:00 a.m. on Tuesday. Very dangerous avalanche conditions exist, per the Gallatin National Forest Avalanche Center. Natural and human-triggered slides are very likely.
In part, the report from the Gallatin National Forest Avalanche Center reads:
Very dangerous avalanche conditions exist in the mountains of Island Park, West Yellowstone and Cooke City. Natural and human-triggered avalanches are likely. Avoid slopes steeper than 30 degrees and lower-angle terrain in the runout zones of avalanche paths.
Slides will fail within the new and wind-drifted snow as wind slab and storm slab avalanches. Since Thursday, the mountains in Island Park have received 40” of snow, equal to 4.1” snow water equivalent (SWE). During the same period, the Lionhead area received 30” of snow and Cooke City received 24” of snow. Yesterday, hurricane-force gusts up to 100 mph transported snow into unstable slabs at all elevations (the strongest gusts were recorded on Lionhead Ridge).
In the Lionhead area, persistent slab avalanches breaking 3-5 feet deep on the weak snow buried in late January are possible. Slides on buried weak layers tapered off a couple of weeks ago, but heavy loading from recent snow could wake these layers up, resulting in large avalanches failing deep within the snowpack.
The specifics of weak layers and types of avalanches are irrelevant today. All can be large enough to injure or kill riders and skiers. Avoidance is critical.
The avalanche danger is HIGH on all slopes.
