An avalanche — a block of snow moving down a slope — occurs most often in the wilderness. Keeping an eye on the forecast, bringing the right equipment and getting training to prepare can help on outings, according to the National Avalanche Center.
The center says that every winter, on average, about 25 people die in avalanches in the United States, adding that “some days are dangerous and some days are not.”
Here’s a look at avalanches, how they happen, and some tips on how to stay safe:
It usually only takes two ingredients to create dangerous conditions: a slope of 30 degrees or more and layers upon layers of snow.
Additional pressure on top of this snow mass due to weight, wind, rain, heavy snow, or movement can cause some layers to break off and slide down.
Sometimes slippage occurs in the form of loose snow, called slush. Avalanches account for only a small percentage of deaths and property damage caused by avalanches, according to the Sierra Avalanche Center.
Other avalanches are slab avalanches, which occur when a large layer of snow breaks off. These are responsible for most deaths.
Another type of avalanche occurs when winds create a cornice of snow that overhangs a ridge or the edge of a steep slope. The overhang can suddenly collapse, surprising anyone below or above it, according to the Colorado Avalanche Information Center.
Movement, rapidly changing weather, wind – any one of these things can trigger an avalanche. But experts say that 90% of slides that cause injury or death are caused by the victim or one of his companions.
This means that people who ski, snowboard, snowshoe, or enjoy other backcountry winter activities should check the avalanche forecast before heading out and make sure they have the proper safety equipment.
Most ski resorts have avalanche mitigation protocols or systems. This often means checking the stability of the snowpack. Remote detonations are also used to intentionally trigger slides and remove dangerous accumulations before skiers are allowed on the slopes, said Chris Lundy, an avalanche specialist at the center. National Avalanche Center.
Don’t think for a moment that you can outsmart one. Dry avalanches typically reach speeds of up to 80 mph (129 km/h) within seconds, according to the Sierra Avalanche Center. Wet avalanches usually travel at speeds of about 20 mph (32 kph).
By comparison, eight-time Olympic gold medalist Usain Bolt set a record of just under 28 mph (45 kph) in the 100-meter dash in 2009 — and that was on a flat course, not a snow-covered slope. Most people caught in avalanches are on the slope when they happen.
The best plan is to make sure you are not in a place that is at risk of it happening. Outdoor enthusiasts can check the forecast at regional avalanche centers or… www.avalanche.org.
If you venture out, it’s a good idea to use the buddy system and be familiar with wilderness first aid. Experts say three pieces of equipment are necessary: an avalanche beacon or transceiver, which sends location signals to others; shovel for testing snow mass or digging out buds; and a thin, collapsible pole for diving into the snow in search of anyone buried. An avalanche airbag backpack that inflates after a skier pulls the trigger giving a person a chance to stay on or near the surface during an avalanche.
On January 5, an avalanche occurred in the Sierra Nevada in California Snowmobile burial Authorities said snow killed him. The snowmobile was initially reported missing, but was found under the snow several minutes later, the Nevada County Sheriff’s Office said in a statement.
In June 2025, Matt is a skater After being exposed to an avalanche on Mount McKinley in Alaska, the highest peak in North America. Denali National Park and Preserve said the skier and his climbing partner, a snowboarder, triggered the avalanche on the 20,310-foot (6,190-meter) peak while descending a slope.
In March of that year, a snow machine was riding on the back side of a popular winter recreation area about 60 miles (97 kilometers) southeast of Anchorage. Triggered by an avalanche After riding on a weak layer of snow that was buried under new snow, according to the National Avalanche Center in Chugach Forest. It was buried about 10 feet (3 m) deep in the slide that was about 500 feet (152 m) wide.
Earlier that month, three Heli-skiers were killed. That accident occurred when they were caught in an avalanche near Girdwood, about 40 miles (64 kilometers) south of Anchorage. Heli-skiing is a type of back-country skiing that involves the use of a helicopter to access remote areas and fresh snow slopes.