Hatcher Pass
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The Bottom Line
Conditions have changed! After a month of relatively stable avalanche conditions, we are going to focus on conservative travel protocols and good backcountry habits to appropriately mitigate today’s avalanche hazard.
Small, human triggered Wind Slabs are possible at Upper elevations on SW thru NW aspects. Natural avalanches are unlikely. These wind slabs will be isolated and may be found on leeward aspects at and near ridgelines, in gaps and passes, and on cross-loaded features.
Small Dry loose avalanches are still possible to human trigger at mid and upper elevations in terrain 40° degrees or steeper.
Even a small avalanche can have serious consequences if traveling above cliffs, gullies, or other hazards.
Special AnnouncementsHatcher Pass Avalanche Center is currently looking for additional board members who are motivated and passionate about sustaining HPAC. If you’re interested in joining our team please email andydennis@hpavalanche.org
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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. |
There were two small human triggered avalanches reported in the forecast area this week. We also had reports of wind slab activity in areas just outside of the forecast area. Click here for more info.
Nov 30th Marmot NW 4300’ small wind slab
11/30 Marmot SW 4200’ small wind slab
| Signal Word | Size (D scale) | Simple Descriptor |
| Small | 1 | Unlikely to bury a person |
| Large | 2 | Can bury a person |
| Very Large | 3 | Can destroy a house |
| Historic | 4 & 5 | Can destroy part or all of a village |
10 mph winds blew from the SE-NE, blew for over 30 hours on Nov 29th and 30th, gusts were up to 20 mph. These winds were able to transport and drift low density snow and create isolated wind slabs 4-12” thick on leeward aspects. Small human triggered slab avalanches will be possible on SW thru NW aspects at the upper elevations, especially at and just below ridgelines.
Where wind slabs have formed, they will be sitting on the weak sugary snow that we have been talking about for all of November. While the weak snow has made riding very fun and enjoyable during the month of November, it will now be the layer of concern in locations where it is buried by wind drifted snow.
2-3 inches of recent snow from last night’s storm, will make identifying this avalanche problem difficult. Use hand pits and pole/probe tests to identify stiff hard snow underneath. Whumphing and shooting cracks are red flags for this avalanche problem.
After a month of stable avalanche conditions and great riding, we are going to be revisiting conservative travel protocols and good backcountry habits. Use low risk travel techniques which include spreading out when traveling uphill or near avalanche terrain. Ride slopes one at a time and be sure that you’re regrouping out of harm’s way.
We have seen and reports have indicated that wind effect is varied across our forecast area. Especially in the peripheral zones, winds may have been stronger and/or longer lived. On the flip side, you may also discover areas that were completely sheltered from the wind and are powder meccas. Conditions can change radically from area to area, or in as little as 10 feet. Complacency is a prescription for surprise, so stay alert, continue to evaluate the conditions throughout your travel, and adjust as necessary.
Shooting cracks were traveling up to 30′ on Marmot. 11/30
| Signal Word | Size (D scale) | Simple Descriptor |
| Small | 1 | Unlikely to bury a person |
| Large | 2 | Can bury a person |
| Very Large | 3 | Can destroy a house |
| Historic | 4 & 5 | Can destroy part or all of a village |
Dry Loose avalanches are still a concern in protected and untracked locations, at upper and mid elevations on all aspects. Human triggered dry loose avalanches are possible and natural avalanches are unlikely. This avalanche problem will be found in terrain that’s 40° degrees or steeper.
Use good sluff management and know what’s underneath you. Avoid terrain traps where avalanche debris can concentrate, exposure above cliffs where even a small avalanche can have big consequences, and steep terrain where it will be easier to trigger this avalanche problem.
