This is Ian Hoyer with the avalanche forecast for Saturday, February 8th, at 7:00 a.m. sponsored by Highline Partners and Spark R&D. This forecast does not apply to operating ski areas.
Snowfall ended yesterday afternoon with 24 hour totals of:
3-4” (0.2-0.4” Snow Water Equivalent) across most of the advisory area
7” (0.6” SWE) near Lionhead
9” (0.8 SWE) near Cooke City
This morning, temperatures are in the single digits and teens F. Winds are 10-15 mph out of the west and northwest with gusts of 30-40 mph.
Skies will be increasingly cloudier the further south you go in our advisory area. Temperatures won’t rise much, with highs remaining in the single digits and teens F. Winds will back off a bit and gusts will die down as they shift more southwesterly. A dusting to 2” of new snow will accumulate by tomorrow morning.
All Regions
Today’s weather won’t feel as intense as the blizzard conditions going on yesterday, but that doesn’t mean that avalanche conditions are any less dangerous. Persistent Slab and Wind Slab avalanches are the primary concerns, with thinner, lingering Storm Slabs a secondary concern.
Weak layers now buried 1-2 ft deep (and deeper on windloaded slopes) have been loaded by snowfall over the last week and Persistent Slab avalanches breaking on them will remain easy to trigger. These weak layers appear to be more widespread around West Yellowstone than in the rest of the advisory area, but they have been found elsewhere (Mt. Ellis observation), so be on the lookout for them wherever you’re traveling.
Windloaded slopes could avalanche regardless of whether or not there are weak layers underneath. With the very strong and shifting winds over the last couple days, any slope could be windloaded, regardless of aspect or elevation. Shifting winds and several rounds of snowfall may have masked visual clues of wind loading, so pay close attention to the feel of the snow under your feet or sled and be wary of any slope until you confirm it hasn’t been loaded.
Storm slab avalanches were easily triggered yesterday and propagated long distances, despite being fairly shallow (Bridgers observation, Hyalite observation). Without active snowfall, these won’t be as reactive as yesterday, but I wouldn’t be surprised if some were still triggered today. So, don’t let your guard down, even on slopes that aren’t windloaded and don’t have recently buried persistent weak layers.
Cautious route-finding is the name of the game today. Either avoid slopes steeper than 30 degrees or carefully evaluate the snowpack before getting onto those steeper slopes. Look for signs of wind-loading, weak layers in the upper 2 feet of the snowpack, or lingering, reactive storm snow.
Across the advisory area, the avalanche danger is CONSIDERABLE today.
Upcoming Avalanche Education and Events
Our education calendar is full of awareness lectures and field courses. Check it out: Events and Education Calendar
February 20, 4-7 p.m. Beacon BBQ at Uphill Pursuits in Bozeman. Come try out different brands of avalanche transceivers (or practice with your own!) with coaching from Friends of GNFAC instructors and free hotdogs.
Every weekend in Cooke City: Friday at The Antlers at 7 p.m., Free Avalanche Awareness and Current Conditions talk, and Saturday from 10 a.m.-2 p.m. at Round Lake Warming Hut, Free Rescue Practice.