Avalanches, an enduring hazard of winter in mountain regions, are making grim headlines again this season, with fatal incidents reported thousands of miles apart in both North America and Europe.
On Tuesday, eight skiers were killed in a massive slide in California, while another remained missing as rescuers battled blizzard conditions. Across the Alps, unusually high avalanche warnings and repeated storms have contributed to dozens of deaths, including several foreign tourists.
The two regions appear to tell different weather stories. California has only recently emerged from a prolonged snow drought, with this year’s totals not considered exceptional by historical standards.
Yet experts say drought followed by intense snowfall can create treacherous layers. Fresh snow struggles to bond with hardened or patchy older surfaces, producing weak, unstable slabs prone to collapse.
Rescue teams, photographed by Reuters, were seen pushing through waist-deep drifts in Nevada County as helicopters and search dogs combed the area for survivors.
Meanwhile in Europe, a sequence of heavy storms has blanketed vast stretches of the Alps. Strong winds piled snow unevenly across slopes, forming dense deposits ready to slide under pressure.
Authorities in Switzerland and Italy have evacuated mountain villages, while power outages and rail disruptions added to the turmoil. A train derailment near Goppenstein in the Swiss canton of Valais underscored how widespread the impacts have become.
Some resorts describe the situation as the worst in decades. At Val d’Isère, officials warned that the snowpack was exceptionally fragile, forcing temporary closures and strict movement controls.
The pattern has prompted renewed questions about whether climate change is intensifying avalanche danger. Scientists caution that the answer is complex, but evidence suggests weather extremes are becoming sharper.
Dr Ben S Pickering of the University of Manchester and the National Centre for Atmospheric Science said climate shifts could bring heavier bursts of precipitation separated by longer dry spells.
Such swings, he noted, may encourage unstable snow structures. Still, he emphasized that avalanche formation depends on multiple factors beyond snowfall alone.
Researchers in the Alps echo that view. Benjamin Zweifel from the Swiss Federal Institute for Snow and Avalanche Research said this winter’s danger stemmed largely from persistent weak layers that formed during cold, snowless stretches.
When storms finally arrived, heavy accumulations stacked on top of fragile foundations, increasing the likelihood of sudden fractures.
Rising temperatures also introduce a different threat: wet snow avalanches. These heavier slides, often triggered by rain or sunshine, are harder to predict and can move with crushing force.
Studies suggest wetter snow may reduce survival chances for victims while thinner cover increases the risk of traumatic injuries from rocks and debris beneath.
Beyond weather, human behavior plays a role. Mountain guides report that more skiers are venturing off-piste in search of untouched powder, often underestimating risks.
Marked trails are usually protected by pre-emptive blasting and grooming, but backcountry terrain lacks those safeguards. Even experienced skiers can trigger slides simply by crossing unstable slopes.
Resorts are trying to adapt. At Tignes, authorities recently imposed temporary lockdowns during peak danger, while La Plagne runs safety days and deploys drones equipped with thermal cameras to aid search and rescue.
Officials urge visitors to carry avalanche transceivers, shovels and probes, travel with partners, and consult daily bulletins before heading out.
Despite advances in forecasting, experts stress that zero risk does not exist in the mountains. The recent tragedies serve as a stark reminder that snow conditions can change rapidly and unpredictably.
As winter tourism rebounds, balancing adventure with caution may be the difference between a memorable day on the slopes and disaster buried beneath the snow.