Avalanche
Avalanche warning services across the Alps have issued stark warnings for Monday, April 13, as a dangerous mix of rain, warming temperatures, and a saturated snowpack drives wet avalanche danger to Level 4 (“high”) in parts of the region. Switzerland’s WSL Institute for Snow and Avalanche Research SLF and authorities in Tyrol are among those raising the alarm, warning that conditions have become “critical” in several high-alpine areas.
In Switzerland, the SLF highlighted Upper Valais as a particular hotspot, where both wet and dry avalanches are expected amid ongoing precipitation and poor overnight refreezing. The warning covers a region that includes some of Switzerland’s most iconic high-alpine terrain and ski areas, such as Zermatt, Saas-Fee, Aletsch Arena, and Belalp.
Meanwhile, in Tyrol, officials say the situation has deteriorated rapidly due to the progressive soaking of the snowpack over recent days, combined with incoming precipitation that includes rain reaching elevations of around 2,500 meters (8,200 feet). Tyrolean authorities have issued Level 4 warnings for multiple mountain groups, including the Weißkugelgruppe, Gurgler Gruppe, Stubai Alps, Zillertal Alps, Venedigergruppe, and Glocknergruppe, while much of the rest of the region remains at Level 3 (“considerable”).
Security Councillor Astrid Mair urged extreme caution, warning that “the avalanche situation is dangerous” and that steep terrain above 30° should be avoided entirely. She added that avalanches may travel far beyond typical boundaries, noting they may run into snow-free terrain and valley floors.
Avalanche forecaster Matthias Walcher explained that water is now penetrating deep into the snowpack, weakening long-standing weak layers that formed earlier in the winter. This process significantly increases the likelihood of spontaneous wet avalanches, particularly on steep west-, north-, and east-facing slopes between 2,200 and 2,500 meter (7,200-8,200 feet).
Medium to large avalanches are expected to release naturally in these zones, without human triggering.
Wet avalanches are a defining hazard of spring in the mountains — and one of the most misunderstood. Unlike dry powder avalanches, wet avalanches occur when meltwater or rain infiltrates the snowpack, breaking down the bonds between snow grains. As the snow becomes saturated, it grows heavier and unstable, eventually collapsing and sliding downhill. While they typically move slower than dry avalanches, they are far denser and more destructive, capable of carrying large amounts of debris. Wet avalanches can present as either wet slab or wet loose snow avalanches.
April is particularly prone to these conditions. Longer days and higher sun angles accelerate melting, while warm nights or cloud cover can prevent the snowpack from refreezing and stabilizing. When rain is added to the equation, especially at high elevations, the process intensifies rapidly. Coupled with the existing weak early-season layer — Altschneeproblem (old snow problem) — conditions are considerably elevating avalanche danger. The weak early season layer combined with some significant mid- and late-season snowfalls have led to Europe experiencing one of its deadliest avalanche seasons in 20 years.
Swiss and Austrian authorities are urging backcountry users to exercise restraint, avoid steep terrain, and remain aware that avalanche paths may extend into unexpected areas. Forecasters expect conditions to improve slightly with cooler temperatures arriving Tuesday night, which could help the snowpack refreeze and stabilize. Until then, however, the message is clear: conditions remain highly unstable.
