Avalanches are most common in steep mountain ranges with heavy snowfall, particularly the European Alps, the Rocky Mountains in North America, and the Himalayas. Within these regions, the specific danger concentrates on slopes angled between 30 and 45 degrees, where snowpack layers are most likely to fracture and release.
The European Alps
Europe is the global epicenter of avalanche activity, with snow avalanches claiming an average of 100 lives per year across the continent. The overwhelming majority of these deaths cluster in four Alpine countries: France, Italy, Austria, and Switzerland. In the 2025/26 season alone, Italy recorded 32 fatalities, France 30, Austria 26, and Switzerland 15. These four countries consistently dominate European avalanche statistics because of the sheer volume of steep, snow-loaded terrain combined with millions of people recreating in it every winter.
Smaller but notable numbers show up in Spain (8 fatalities in 2025/26, mostly in the Pyrenees), Slovakia (6), and Slovenia (3). Countries with flatter terrain or lower mountains, like Germany, Finland, and the UK, recorded zero deaths that same season.
North America’s Riskiest States
In the United States, Colorado is by far the most dangerous state for avalanches, accounting for 33% of all avalanche deaths in a 45-year analysis. Washington state follows at 13.2%, and Alaska at 12%. Colorado’s outsized share comes from a combination of factors: its continental snowpack tends to develop weak, sugary layers near the ground that persist all season, and the state draws enormous numbers of backcountry users to its high peaks.
Washington’s risk is driven by a different snowpack type. The Cascade Range receives massive amounts of wet, heavy snow from Pacific storms, and its maritime climate produces frequent natural avalanche cycles. Alaska’s contribution comes from both its coastal ranges, which get buried under deep maritime snowpacks, and its remote backcountry, where rescue is often slow or impossible. Utah, Montana, and Wyoming also see significant avalanche activity, though at lower total numbers.
The Himalayas and Central Asia
The western Himalayas contain some of the most avalanche-prone terrain on Earth. In India’s Himachal Pradesh state, roughly 8% of the region is classified as highly susceptible to avalanches, with the districts of Lahaul and Spiti being particularly dangerous. Major tourist towns like Kullu, Manali, and Keylong sit within high-risk basins, and the local economy depends heavily on snow tourism.
The 479-kilometer Leh-Manali highway, which connects Ladakh to the rest of India, passes through multiple zones classified as high or very high avalanche susceptibility. The stretch from Chandra Bridge through Keylong and Darcha to Baralacha La is especially exposed. Sections of this road close regularly due to heavy snowfall and avalanche activity. The Padum-Darcha road, a critical link to the Zanskar region in Ladakh, faces similar risks. Recreational areas like Dhundi and Solang are also classified as highly susceptible zones.
Beyond India, Nepal, Pakistan’s Karakoram range, and the mountains of Central Asia (including the Tien Shan and Pamir ranges) all experience frequent avalanche cycles, though systematic data collection in these regions is less developed than in Europe or North America.
What Makes a Slope Dangerous
Geography alone doesn’t determine avalanche risk. The angle of the slope matters enormously. Most avalanches release on slopes between 30 and 45 degrees, with the highest trigger probability clustering around 38 to 40 degrees. On slopes steeper than about 45 degrees, snow tends to sluff off in small amounts before it can accumulate into a dangerous slab, so the risk actually decreases at very steep angles.
The snowpack structure underneath the surface is the other critical ingredient. Avalanches need a weak layer buried beneath a cohesive slab of snow. These weak layers form in several ways: surface hoar (frost that grows on the snow surface during clear, cold nights and then gets buried by the next storm), depth hoar (large, fragile crystals that develop near the ground when the snowpack has a strong temperature gradient), and faceted crystals that grow around crusts within the snowpack. Persistent weak layers are especially dangerous because they can lurk deep in the snowpack for weeks or months, waiting for enough weight from new snow, wind loading, or a skier’s weight to trigger a collapse.
Aspect matters too. In the Northern Hemisphere, north-facing slopes hold cold snow longer, which promotes the growth of weak layers. South-facing slopes get more sun, which can stabilize the snow but also trigger wet avalanches in spring. Wind-loaded slopes, where snow has been deposited on the lee side of a ridge, carry extra weight that stresses whatever weak layers exist beneath.
Peak Season for Avalanches
In the Northern Hemisphere, avalanche season runs roughly from December through May. Winter months (December through February) historically produce the most avalanche activity, driven by storm cycles that load slopes with fresh snow and wind. Spring (March through May) brings a different type of danger: warming temperatures weaken the snowpack from the surface down, triggering wet avalanches that can be massive and destructive.
Research from northern Norway shows an interesting shift over recent decades. Winter avalanche activity has slightly declined while spring avalanche problems have increased, likely driven by warming temperatures. In high-elevation areas, wet avalanches are becoming the dominant problem later in the century, replacing wind slab and persistent weak layer avalanches that historically peaked in midwinter. This pattern is consistent with what avalanche forecasters are observing across many mountain ranges worldwide.
Who Gets Caught
The profile of avalanche victims has shifted dramatically over the past several decades. In the United States between 1951 and 2013, snowmobilers became the largest group killed in avalanches, accounting for 23% of all fatalities. Backcountry skiers were a close second at 22%, followed by climbers at 16% and people skiing out of bounds from ski resorts at 12%.
The rise of snowmobile fatalities is striking. The first recorded snowmobile avalanche death in the U.S. occurred in 1968. By 1999, snowmobilers and snowboarders combined accounted for fewer than 10% of avalanche deaths. They now represent 28%. Snowmobile deaths increased by about 7% per decade, while backcountry snowboarder deaths grew by 2% per decade. Meanwhile, deaths among climbers and highway workers have declined, reflecting better infrastructure protection and possibly changes in climbing practices.
The common thread is that avalanche fatalities are overwhelmingly a backcountry recreation problem. People traveling on uncontrolled snow in the mountains, whether on skis, snowboards, snowmobiles, or on foot, account for the vast majority of deaths. The terrain hasn’t changed, but the number of people venturing into it has grown enormously.