Aspect: N-NW-W

Elevation: Tree line and above

Bottom Line: Moderate to strong S-SE-E winds with 4-8″ of new snow from 3/21-22 has top loaded and cross loaded slopes greater than 30 degrees on N-NW-W aspects. Wind loaded aspects, especially terrain features below ridge tops, peaks, gullies, aprons, bowls and openings in the trees should be considered suspect. It is important to realize that wind deposited zones could be thin at the edges around trigger points like rocks and cliffs, while the majority of loaded snow in the middle is deep and destructive. Human triggered avalanches are likely while natural avalanches are possible. Dangerous conditions. Careful snowpack evaluation, cautious route finding and conservative decision making are essential. 

Travel Advice:

• Look for blowing or drifting snow or rapid loading.
• Avoid slopes with textured surfaces, suspect loading, or pockets of wind slab.
• Identify and avoid shallow areas including trigger points around rocks, cliffs, and trees.
• Understand wind slabs can break in shallow spots and propagate deeper.
• Look, listen and feel for shooting cracks, collapses and hollow sounds.
• Avoid terrain trap areas such as cliffs and gullies, and areas where it is hard to escape off to the side.

Additional Consideration:

• We believe deeper persistent layers are currently dormant. However, you could still trigger a deeper persistent slab in thin or shallow snow even if we haven’t had recent feedback or avalanche activity.
• With the beginning of March comes a higher sun angle than we have seen for the last couple months. Surface warming will begin to be prevalent on solar days, especially around exposed rocks and creating thin and/or weak spots where you could trigger these deeper layers.
• A variety of wind loading patterns throughout the season have created sizeable cornices on all aspects near mountain tops and ridgelines. Beware that cornices can break much further back than expect, can trigger deeper persistent weak layers and are sensitive to warming, temperature changes and direct sunlight.
• Remember that persistent slabs are unpredictable and that tests and observations can be unreliable. A probe can be very helpful to determine snow depth and presence of deeper buried weak layers by noting resistance as the probe moves through the snow.
• Continue to utilize safe travel protocol, wide margins of safety, and collect more information when it comes to entering committing terrain.
• Loose snow avalanches over terrain features will be amplified by direct sunlight and increasing temperatures during the day, avoid overhead hazard by utilizing timing.

Aspect: All

Elevation: Near and Above Treeline

Bottom Line: Recent snow deposits and wind loading sit over a variety of old snow surfaces from earlier in the month. These include solar aspects with sun or temperature crusts, soft weak facets on sheltered slopes and blasted hard patches from south and north winds. Overnight settlement of this week’s snow and warming daytime temperatures stress buried weak layers and stiffen the overlying slab. This could increase the reactivity of triggering a persistent slab. Human triggered avalanches are possible while natural avalanches are unlikely. Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.

Travel Advice:

• Think about the consequences of a wide hard slab breaking before you commit to a slope. How can you avoid triggering an avalanche? What is your plan if one is triggered? Always reduce your exposure to these risks as much as possible. Travel one-at-a-time in avalanche terrain, and only group up in safe areas, with a wide safety margin.
• Stick to slopes less steep than 30-degrees while in the alpine. If you choose to venture onto steeper slopes, carefully evaluate them by digging, probing, and testing them.
• Look for shooting cracks, whumphing or collapsing that indicate a stiffer slab over weaker snow. 
  
• Hard wind slabs can break above you, take into consideration extra safety margins.
• Remote triggers are possible to common, even from flat terrain. Give runout zones a wide berth.
• Persistent slabs are unpredictable, don’t get surprised. Gather information to help confirm suspicions and make assessments.
• Probe and feel for slabs underneath you.