Galena Summit & Eastern Mtns

Last Thursday and Friday's snowfall created dry snow instabilities: natural loose snow "sluffs" (view Observation near Banner Summit), and probably some wind slabs in alpine and upper elevation terrain. While the recent snowfall has stabilized in most locations, Monday's expected squalls could drive a fresh round of dry snow avalanche problems and activity in the eastern Pioneer Mtns. A summary of what to expect Monday and Tuesday:  

Wind Slab Avalanches: Watch for fresh, sensitive wind slabs in upper elevations in the Pioneer Mtns. Over the entier forecat area, you could find older, harder-to-trigger slabs that formed last week near cornices and ridgelines, on the sides of cross-loaded gullies, and in alpine cirques. Any of these slabs could overlie weak faceted snow or thin crusts on some slopes, making avalanches wider and easier to trigger than you might expect. Watch for drifts, dunes, and smooth pillows of snow, signs the wind has been at work. Cracks shooting out from your boards or sled are a clear sign you've found a sensitive slab.

Dry Loose Avalanches:  On very steep slopes where more than about 6 inches of fluffy (not crusty) snow exists, natural and human-triggered loose snow avalanches (sluffs) are possible. Think about where these small but pushy avalanches might carry you before committing to skiing or riding large or consequential avalanche paths. Any periods of direct sunshine could produce small, natural loose snow slides, especially in wind-protected terrain near rocks and cliffs.

As skies clear and temperatures warm from Wednesday on, wet avalanches will become our primary concern. 

Wet Loose Avalanches:  Steep slopes with more than about 6" of "newer" snowfall (not crusts or corn snow) are most likely to produce surficial wet loose avalanches. Look for rollerballs and pinwheels of snow moving downslope as an indicator that it's time to move to colder, drier slopes (or exit to the trailhead). The threat of these slides will follow the sun around the compass:  E-SE aspects in the morning, S-SW facing slopes by noon, and W-NW aspects later in the day.  Even shady, NW-N-NE aspects could become problematic as temperatures warm to the 50s F. Very steep, rocky, sun-drenched avalanche paths that are protected from the wind are most suspect. As always, beware of and avoid any steep slopes where you are falling deep into a sloppy, wet snowpack. The time windows to find supportable surface crusts will shrink or become non-existent by Friday and Saturday. 

Recent Observations: 

• April 24 - Banner Summit 2: CLICK HERE
• April 24 - Banner Summit: CLICK HERE
• April 23 - Bench Hut: CLICK HERE

SNOWPACK AND AVALANCHE GENERAL INFORMATION

Some basic points to remember until you put the sleds and boards away for the summer:

• Spring weather can rapidly alter snow conditions and snow stability. Think minutes and hours rather than days and weeks.
• Storm slab and wind slab avalanches are most likely during and immediately following a storm. 
• Short periods of sunshine after a snowstorm can quickly create wet loose avalanche instabilities.
• Keep wet slab avalanches in mind, especially during rain events and when we go days without the temperature dropping below freezing. Many shady, upper elevation slopes have not yet gone through a "spring transition". Travel cautiously in this terrain when rain or hot, sunny spells push meltwater deeper into the snowpack. 
• Give cornices a wide berth and don’t linger beneath them. 
• Complicated, consequential terrain doesn’t get less complex or serious in the spring and summer. Respect the mountains, maintain safe travel procedures, and keep your guard up.
  
  

OBSERVATIONS

Even though we’re done issuing forecasts, we’ll continue posting observations when we get out in the mountains. We encourage you to do the same. Please let everyone know what you’re seeing out there, especially if you see or trigger any avalanches. We’re always trying to collect as much information as possible about large wet slab avalanches (where, when, etc); let us know if you come across any of these beasts in your travels. There are several ways to stay connected and to share what you see:

Submit an Observation:

• CLICK HERE for the online form
• Download the Avy App: Apple | Android
• Email us: info@sawtoothavalanche.com
• Text us at 208-481-5921

 

View Observations:

• CLICK HERE to view Observations.
• CLICK HERE for details on recent Avalanches.
• CLICK HERE to view our Photos & Video page.