Hatcher Pass
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The Bottom Line
The avalanche danger today is LOW in the morning, rising to CONSIDERABLE in the afternoon for Wet Avalanches at low and mid elevations, most likely in the afternoon and evening on steep SE to SW aspects. Most avalanches will be small in size although large avalanches up to D2 will be possible on S aspects at low and mid elevation in the pm. A MODERATE danger exists at upper elevation for wet avalanches in the afternoon on SE to SW steep slopes.
Cornices are huge and will be possible for a human or dog to trigger today. Cornices will have the potential to trigger larger sluffs or slab avalanches that may fail to the ground. Large cornice chunks have been observed below many leeward slopes.
A slightly cooler trend this week with overnight freezing temperatures at upper elevation has significantly improved conditions. Time of day and aspect choice will be key for pure enjoyment, staying safe, and avoiding avalanches.
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| Travel Advice | Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features. | Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern. | Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding, and conservative decision-making essential. | Very dangerous avalanche conditions. Travel in avalanche terrain not recommended. | Extraordinarily dangerous avalanche conditions. Avoid all avalanche terrain. |
| Likelihood of Avalanches | Natural and human-triggered avalanches unlikely. | Natural avalanches unlikely; human-triggered avalanches possible. | Natural avalanches possible; human-triggered avalanches likely. | Natural avalanches likely; human-triggered avalanches very likely. | Natural and human-triggered avalanches certain. |
| Avalanche Size and Distribution | Small avalanches in isolated areas or extreme terrain. | Small avalanches in specific areas; or large avalanches in isolated areas. | Small avalanches in many areas; or large avalanches in specific areas; or very large avalanches in isolated areas. | Large avalanches in many areas; or very large avalanches in specific areas. | Very large avalanches in many areas. |
Natural and human triggered wet-loose and natural wet-slabs were observed most of the week. Most wet-loose were small in size, in terrain 40° and steeper, and on ALL aspects, and all elevations. The largest avalanches were up to D2 in size, at all elevations, on SE to S aspects.
Many large cornices have failed naturally, triggering persistent slab avalanches. Large to extra large cornice chunks have fallen naturally too.
3/29 Wet loose and wet-slab. 4500′ SE Birthday / High Grade Pass.
Cornice failures, either naturally, or human triggered, will be possible today up to D2 or larger in size, on leeward aspects at upper elevation. This is a high consequence hazard.
A large cornice fall triggered a D2 persistent slab this week in the Rae Wallace chutes. Last week, a dog triggered a cornice fall that triggered a D1.5 persistent slab to the ground.
Cornices are large and can be difficult and dangerous to assess. Our recommendation is to assume that cornices are LARGE on all leeward aspects at upper elevation, and to give cornices a wide berth of 20 feet or more. Cutting cornices of this size as a stability tool is not recommended nor effective.
Significantly weakening Cornices Top of Cable Valley West Pass
A solid overnight freeze will keep most snow surfaces frozen this morning at mid and upper elevation. Natural avalanches will be possible today, and human triggered avalanches will be likely in the afternoon on SE to SW aspects at mid and low elevations, mostly small, but up to D2 on S aspects, on slopes 40° and steeper. It will be possible to human trigger mostly small ,wet loose at upper elevation on steep SE to SW aspects in the afternoon.
Natural, wet loose avalanches have been observed all week, mostly on southerly aspects. Some have trenched to the ground.
A small wet loose avalanche can easily treek a knee, or push you into terrain traps.
Timing is key to your safety. The snow will transition through the day. Pay close attention to the snow surface. As it heats through the day it will become increasingly saturated. Wet snow, deeper than your ankles, will be dangerous on slopes 40 degrees and steeper, and become more likely to entrain snow, increasing the likelihood and consequence of any wet-loose. Wet-loose sluffs are avoidable with good decision making and terrain choices.
Wet slabs will be possible to human trigger on SE to W aspects at mid and upper elevation on slopes 30° and steeper, and up to D2 in size, in the afternoon. Poor structure and the lack of a slab will alleviate this concern at low elevation in most locations.
Wet slabs have also been sympathetically triggered by wet loose avalanches this week. For the most part, wet slabs are hard to predict. We did observe 3-5 natural wet slabs on SE to SW aspects this week. Expect the wet-slab cycle to continue and grow in size as spring weather continues.
