Northern Gallatin Range

Strong winds, a few inches of snow overnight and more on the way today are keeping the snowpack right at its breaking point. Human-triggered Persistent Slab avalanches, as well as Wind Slab avalanches, remain likely at higher elevations. Wind-loaded slopes and those that hold old snow from pre-Thanksgiving are the most concerning. Watch for wet snow at low elevations.

Avalanche conditions are very dangerous in the mountains near Cooke City. Yesterday, near Daisy Pass, a snowmobiler triggered a very large Persistent Slab avalanche from low on the slope and was fully buried for 12-15 minutes before being dug out (photos and more details). This very close call is just one of many large slides that have broken over the last week on weak snow near the ground (Miller Mountain, Henderson Mountain, the Fin). This weak snow has proven itself to be unstable and has now been loaded again by more snowfall overnight, additional wind loading, and it’s still snowing and loading this morning. 

Do not mess with avalanche terrain today near Cooke City. Stay off of and way out from underneath all slopes steeper than 30 degrees. The avalanche danger is HIGH.

In the N. Gallatin and N. Madison Ranges, strong winds, a few inches of snow overnight and more snow on the way today are keeping the snowpack right at its breaking point. Human-triggered Persistent Slab avalanches, as well as Wind Slab avalanches, remain likely at higher elevations. Wind-loaded slopes and those that hold old snow from pre-Thanksgiving are the most concerning. The avalanche danger is CONSIDERABLE.

Elsewhere across the advisory area (the Bridger Range, S. Madison and S. Gallatin Ranges, Lionhead and Island Park areas), Persistent Slab avalanches breaking near the ground are also the major concern, but without much recent loading, they will not be so easily triggered. Dig down to look for and test the old snow before committing to steep slopes. The avalanche danger is MODERATE in these areas.

With above freezing temperatures and rain at low elevations, we may see some small Wet loose avalanches today. I don’t expect these to be a major hazard, but unusual weather can cause unusual avalanches, so be on alert. If the sun comes out this afternoon, that will add to this concern. Ice climbers getting out in Hyalite Canyon for Ice Fest should watch for roller-balls and pinwheels that indicate increasing instability. Retreat if the steep terrain above your position is becoming unstable.