Haines Pass

Avalanche danger remains high as additional new snow, wind loading, and rising temperatures continue to overload weak, sugary layers in the snowpack. New and wind-drifted snow over these weak layers is producing unstable conditions, and natural avalanches are expected. Avoid avalanche paths and runout zones. Even small features on slopes steeper than 30 degrees—especially gullies and steep-to-flat transitions—can produce dangerous avalanches.

Snowpack & Avalanche Problems

A series of low-pressure systems, following three weeks of Arctic outflow winds and record-setting low temperatures, has created a unique and potentially dangerous snowpack structure. Weak, sugary faceted snow exists near the surface on slopes that were sheltered from northerly outflow winds. Once buried beneath new storm snow, this layer becomes increasingly difficult to assess and forms a smooth, low-friction bed surface. Cold storm snow that fell during near-zero temperatures further contributed to an upside-down snowpack structure.

Since Saturday, December 27th, the region has received approximately 3–6 inches of snow water equivalent (SWE), translating to several feet of new snow in the mountains. As this heavy new snow accumulated—often rapidly—failures within the new snow became increasingly likely. These avalanches may step down to deeper weak layers, allowing fractures to propagate widely across terrain and produce large, destructive natural and human-triggered avalanches. While snowfall rates and totals have varied across the region, the combination of a deep new load over persistent weak layers has significantly increased avalanche potential.

Cold temperatures during the storm limited settlement, preserving stress within the snowpack. As temperatures rise and winds increase, additional loading from settlement and wind-drifted snow will further stress weak layers and promote slab formation. In areas where the weak, sugary faceted snow did not form due to wind scouring, bonding within the storm snow may be stronger; however, storm slab instabilities and wind-loaded slopes remain concerns—particularly as northerly winds transport snow onto leeward aspects. With multiple overlapping instability factors present, managing risk by changing aspect or elevation alone is unlikely to be effective when selecting terrain.

Travel Advice 

Given the current snowpack structure and the large amount of recent loading, avoiding avalanche terrain remains the safest approach. This includes slopes steeper than 30 degrees and connected terrain—meaning even flat areas below steep slopes overhead. Avalanches may run farther than expected, so stay out of runout zones such as gullies, valley bottoms, and other terrain where debris can accumulate. Even relatively small slopes can have serious consequences.

Avalanche hazard remains elevated as a deep load of new snow continues to stress weak layers. Rising temperatures will promote settlement and additional slab formation, while increasing winds will redistribute snow and further load leeward slopes. The most dangerous conditions often occur during periods of additional loading and as the snowpack adjusts after storms. Watch closely for signs of instability, including recent natural avalanches, cracking, collapsing, and whumphing—clear indicators that weak layers are failing. 

While new snow contributes to long-term snowpack development, patience is critical while persistent weak layers remain active. Deep snow can make lower-angle terrain more difficult to travel, increasing the temptation to move into steeper slopes. Continue gathering observations and hold off on higher-consequence terrain until the snowpack has time to adjust.

Patterns show that accidents often occur when instability is highest, both during storms and on clear days following a storm when persistent weak layers remain in the snowpack. 

https://utahavalanchecenter.org/avalanche-danger-scale 

Known Weak Layers

With limited observations over the past month, there is a high degree of uncertainty around how previously identified weak layers are responding to recent snow, wind, and prolonged cold temperatures. These layers may become more reactive as they are loaded by new snow and wind.

Layers of concern include:

• Very cold early storm snow produced slick dendrites and plates December 27-28th
• Near-surface facets (sugary snow) that formed between December 7th–26th
• A buried surface hoar layer reported in mid-November near Chilkat Pass
• A widespread melt-freeze crust that formed in early December up to approximately 2,500–3,000 feet

Additional Hazards

Near-zero temperatures, severe winds, and heavy precipitation add another layer of hazard. These conditions can slow rescue efforts, reduce mobility, and increase the severity of injuries if something goes wrong in the mountains.

Heavy snow and warming temperatures also increase the risk of roof avalanches and snow shedding in town. Use caution around buildings, stay clear of roof edges, and keep exhaust vents and intakes clear of snow.

Early Season Considerations

Conditions will continue to evolve, and the snowpack will vary across short distances as you move between aspects, elevations, and terrain features. Keep assessing the snow as you travel. We currently have very limited information and funding, so please read and submit observations and report any avalanches you see.  Consider supporting the center by donating or becoming a member or community partner.

It’s still early season. Practice companion rescue skills with your partners and make sure everyone’s beacon, shovel, and probe are functioning properly—and that each person knows how to use them. Use extra caution around shallow snowpack areas, rocks, cliffs, and buried vegetation that can increase the risk of injury in a fall or crash.

Regular general avalanche information products are published every Friday morning at 6am during the 2025-2026 winter season.