Hatcher Pass

Recent wet loose and/or wet loose that triggered wet slabs were observed Friday on Arkose Ridge, Punk Spines, SE face of Skyscraper, Eldorado Bowl, Martin Mine, SW face of Marmot, to name a few.  Click here for recent 4/21 observations.

4/21 Marmot SW face, Natural Wet-Loose 4000′

4/21 Punk Spines W aspect 3500′ , old Persistent slab in background from 4/13 and new 4/20 wet loose in middle of photo.

4/21 Skyscraper SE aspect 4000, Natural wet-loose that triggered a wet slab avalanche.

4/21 Arkose ridge W aspect 3500′ Wet loose triggers wet slab with debris seen in gully on bottom right of photo.

On Saturday 4/15, two avalanches occurred, a near miss on Hatch Peak and a full burial on the Willow side of Hatcher Pass (previously thought to be April Bowl).

4/15 Hatch peak avalanche as seen from the air shortly after the incident. Unbelievably, no one was caught or carried. photo: Jed Workman

4/15 Willow side of HP avalanche accident that fully buried one person who sustained minor injuries.

Navigating the backcountry in springtime can be challenging.

Wet loose and wet slab avalanches have been observed and reported in the past few days on East thru West aspects (E to S to W). Expect these avalanche problems to remain active and become more prevalent on the entire compass and at all elevations as temperatures rise, combined with a lack of overnight freezing. 

Maintaining strict habits on safe travel protocol is a good habit during ‘green light’ conditions as well as red light. The main things are exposing only one person at a time, having escape routes planned, watching your partners closely, carrying and knowing how to use your rescue equipment.

4/21 SE 4000′ Skyscraper, Wet loose triggered wet slab. This is the first cycle of wet slabs we have seen this season.

Springtime Avalanche Concerns

1. Loose Wet Avalanches- Loose wet avalanches are typically the first avalanches we see as the snowpack warms up. They can be triggered by snow heating up especially near rocks and cliffs on steep slopes.  While they are relatively small and manageable on their own, they can be dangerous if they pick up enough volume, or if they push you into terrain traps. They can also trigger larger slab avalanches as they travel downhill. They are typically preceded by rollerballs or pinwheels rolling down slopes as they heat up. This in an easily avoidable avalanche problem. Expect wet loose sluffs to be possible on all aspects in steep terrain.

Wet loose debris from west and southwest gully sidewalls that buried the boot pack couloir on Rae Wallace this week. This hazard now exists on all aspects as we move well into springtime conditions.

2. Wet Slabs– Wet slab avalanches  Wet snow avalanches are caused by melt water which weaken the bonds (strength) of a buried weak layer, decreasing the strength of the snowpack which can lead to wet loose avalanches on the snow surface or larger wet slab avalanches that release either on weak layers within the snowpack or on the ground.  Wet slab avalanches can be highly destructive and require careful evaluation of the snow surface conditions to minimize your exposure. The best indication of wet slab avalanche potential is to monitor how deep you are sinking into the snow surface and pay attention to any smaller wet loose avalanches that are either human triggered or naturally triggered.  A common avalanche proverb says that three nights in a row of no refreeze is an omen of major wet slab avalanches. We have not seen freezing temps below 3500′ for two nights. It is best to avoid avalanche terrain and runout zones during these periods as the ingredients for large and destructive wet slab avalanches are all in place.

This video was shared with HPAC. Exact location is unknown. The rider triggered a wet slab.

3. Cornices – Cornices are very large especially on the Marmot ridgeline above Rae Wallace. Cornices can break off naturally, especially during warm weather when they start bending downhill. Simply avoid being underneath or near the tops of large cornices as they break farther back than expected. Cornices can trigger sluff and slab avalanches and are unpredictable this time of year.

4. Glide Avalanches– A separate but related avalanche problem is glide avalanches.When they happen is mostly unpredictable, however, where they happen is generally predictable because there is often a huge crack in the snowpack. Glide cracks are more likely during periods of active melting of the snowpack. Common places to find glide avalanches are places with rock slabs or a smooth ground surface which are common in much of the terrain at Hatcher Pass. Avoid spending time underneath as it could release at any time and create a large and destructive avalanche..