Unstable Snowpack Leads to Above-Average Avalanche Incidents This Winter

Switzerland confronts a harrowing winter season as the WSL Institute for Snow and Avalanche Research (SLF) confirms a staggering spike in avalanche incidents across the massif. This is not a typical winter; it is a season defined by volatility. By the end of March 2026, the Swiss Alps witnessed 171 separate avalanche incidents involving humans—a dramatic leap from the ten-year average of 127. The mountains are speaking, and the message is one of extreme instability. While the peaks remain a magnet for enthusiasts, the hidden structural integrity of the snow has crumbled, turning pristine slopes into potential death traps. This surge in activity demands immediate attention from the public and authorities alike as the hydrological year continues to unfold.

A staggering 244 people were caught in the path of rushing snow this season, far surpassing the decade-long average of 182 individuals. The data paints a picture of a high-stakes winter where nearly 40% more people found themselves battling the elements than in a standard year. Among these, 37 individuals were completely buried, disappearing beneath the white weight of the Alps. However, in a testament to Swiss search-and-rescue efficiency and perhaps a stroke of collective luck, the fatality count stands at 15—a figure that, while tragic, remains in line with historical norms. This disconnect between the number of incidents and the death toll suggests that while the mountains are more active, rescue technology and rapid response times are currently holding the line against a higher catastrophe.

The root of this year's chaos lies deep within the snowpack, where a fragile foundation of 'old snow' has created a ticking time bomb. After an early start in November, a dry and sunny January allowed large temperature gradients to transform the base layers into a sugary, unstable crystalline structure. These weak layers are the primary culprits in 13 of the season's fatal accidents. Experts warn that these conditions are notoriously difficult to detect; even seasoned mountain guides can be deceived by a surface that looks firm but hides a hollow, collapsing base. When these deep layers fail, they trigger massive, full-depth avalanches that carry enough force to snap mature trees and bury entire valley roads. It is a invisible enemy that has persisted throughout the 2025-2026 cycle.

The crisis peaked in mid-February when a relentless atmospheric river dumped up to 150cm of fresh powder on the Lower Valais in a matter of days. This massive weight proved too much for the fragile base, forcing authorities to raise the avalanche danger to Level 5—the maximum possible rating—on February 17th. For nearly six weeks, between January 10th and February 22nd, avalanches involving people occurred almost daily. Regions like Valais, Graubünden, and Ticino bore the brunt of the onslaught. Even as the danger briefly eased in early March, the southern side of the Alps saw a secondary spike in activity. The sheer volume of snow, combined with the structural weakness of the pack, created a 'perfect storm' of natural hazard that paralyzed high-altitude transit and tested the limits of Swiss infrastructure.

As we approach the end of the hydrological year on September 30th, Switzerland must reckon with the implications of this volatile season. The 2025-2026 winter serves as a stark reminder that traditional mountain knowledge is being challenged by increasingly erratic weather patterns. While the immediate danger may subside with the spring thaw, the lessons of this 'above-average' year must be integrated into future safety protocols. For the Swiss public, the message is clear: the mountains are changing. Vigilance is no longer optional; it is a prerequisite for survival. As the SLF prepares its final tally, the focus shifts to how we can better predict these deep-layer collapses to ensure that next winter, the number of people 'caught' plummets back toward safety. The Alps remain our greatest treasure, but this year, they have proven to be our most formidable adversary.