Banner Summit

We've seen gradually warming temperatures over the past few days, and high temperatures are forecast to climb into the 50s F in the mountains both Monday and Tuesday. Surface refreezes are expected to break down quickly with these warm temperatures and powerful spring sunshine, so time your corn harvests early. Conditions will change rapidly Wednesday with a solid storm thumping the area. Plan to adjust your terrain choices to adapt to more wintery dry-snow avalanche problems later this week. These are the avalanche problems we'd expect to see this week:

Wet Loose Avalanches: Moist unconsolidated surface snow often acts predictably and yet can easily push you into places you'd rather not go. Be aware of deteriorating conditions as the snow becomes wet, greasy, and challenging to ski and ride in. Look for rollerballs and pinwheels of snow moving downslope as an indicator that the surface is too hot and that it's time to move to colder, drier slopes (or exit to the trailhead). Expect any lingering natural avalanche activity to 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.  Very steep, rocky, sun-drenched avalanche paths that are protected from the wind are most suspect.

Wind Slab Avalanches: In areas where you find more than 6" of new snow midweek, expect to find fresh wind slabs beneath cornices and ridgelines, on the sides of cross-loaded gullies, and lower in alpine cirques. The new slabs could overlie weak faceted snow or thin crusts that formed during clear days/nights 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. Additionally, storm slabs may form due to fluctuating temperatures during the storm, especially in middle-elevation terrain (like these observed on Friday). 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 that receive 6 or more inches of fresh snow Wednesday, natural and human-triggered loose snow avalanches (sluffs) will become more likely. Think about where these small but pushy avalanches might take you, especially in exposed terrain, before committing to riding a slope. Expect direct sunshine to quickly initiate small, natural, loose avalanches when it reappears after the storm.

Recent Observations: 

• April 17 - Titus Ridge: CLICK HERE
• April 16th - Copper Mtn near Banner Summit: CLICK HERE
• April 16th - East Fork Baker Creek: CLICK HERE
• April 16th - Mushroom Ridge near Galena Lodge: 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.