What is an avalanche?
An avalanche is a mass of material moving rapidly down a slope.
Snow avalanches are the most common, occurring in mountainous areas such as Europe and North America.
Keep reading to learn more about what causes an avalanche, the different types of avalanches, the deadliest disasters on record and more.
Although we have never needed to respond to an avalanche, ShelterBox provides emergency shelter following different types of disasters.
stay informed
What causes an avalanche?
A snow avalanche is caused when a large mass of snow suddenly moves downhill. These usually occur during winter, but they can be triggered any time during the year.
For an avalanche to occur, three elements are needed: a surface bed of snow, a weaker layer that is collapsible, and an overlaying snow slab. It’s very common for an avalanche to happen during and immediately after a snowstorm.
Storms, temperature, wind, slope steepness, terrain, vegetation, and general snowpack conditions can all influence the possibility of an avalanche happening.
But humans can also often trigger avalanches. When somebody walks or rides over a slab with an underlying weak layer, it causes the weak layer to collapse. As a result, the overlaying mass of snow fractures and start to slide, causing an avalanche.
By changing the environment, people play a role in making disasters more frequent and intense.
Is an avalanche a natural disaster?
No. An avalanche is often called a “natural disaster,” but its causes can be linked to human impact on the environment.
While avalanches have occurred naturally for centuries, the effects of climate change driven by human activities like deforestation, urbanisation, and global warming – are altering weather patterns and increasing the likelihood of extreme events. Human activities are destabilising ecosystems and disrupting snowpacks, making avalanches more frequent or severe in certain areas.
Why disasters are not naturalDid you know?
90% of avalanche incidents involving people are triggered by the victim or someone in the victim’s party.
What is a Slab avalanche?
A slab avalanche is a type of avalanche where a big, solid layer of snow, called a “slab,” breaks apart from the snow beneath it and moves downhill.
Once a slab avalanche starts, the slab shatters into many separate blocks. These snow blocks break up into smaller pieces. Some of the pieces rise into the air as a moving cloud of icy particles.
The cloud races downhill at very high speeds. These are especially threatening to people skiing, hiking or snowboarding because of their thickness and speed. Each year, over 150 people are killed because of avalanches worldwide.
What is a sluff avalanche?
A smaller slipping of loose snow. Sluff avalanches occur when the weak layer of a snowpack is on the top. Sluffs and slabs are the two main types of snow avalanches.
What is the difference between a slab avalanche and an avalanche?
In general, an avalanche refers to any large amount of snow that quickly slides down a slope.
A slab avalanche is a lot more dangerous, and it occurs when the weak layer lies lower down in a snowpack. This layer is covered with other layers of compressed snow. The weak layer breaks off once the avalanche is triggered, pulling all the layers on top of it down the slope. These layers tumble and fall in a giant block, or slab.
Stay informed on environmental disasters
Does climate change cause avalanches?
Climate change significantly increases avalanche risk. Rising temperatures, more intense storms, and shifts in snowpack stability make avalanches more frequent and more dangerous.
Higher temperatures contribute to wet snow avalanches, which occur when melting and refreezing weaken the snow layers, creating instability. Additional factors, such as seasonal temperature changes, increased rainfall, and heavy snowstorms, further destabilise the snowpack.
As these risks grow, it becomes essential to adjust avalanche forecasting methods and implement stronger safety practices to mitigate the dangers.
How climate change affects disastersWhat was the deadliest avalanche in the world?
According to Guinness World Records, the deadliest avalanche on record took place on 13 December 1916, near the Gran Poz summit of Monte Marmolada, Italy.
That day became known as White Friday after thousands of soldiers from Austria-Hungary and Italy were killed by a number of avalanches in the Dolomites.
Deadly avalanches on record
Other deadly avalanches that have happened during the years are:
– Yungay, Peru. An avalanche on Mount Huascaran, Peru, buried the town of Yungay in snow and ice in May 1970. The incident killed approximately 18,000 people.
– North Ossetia, Russia. At least 125 people were killed as the Kolka glacier collapsed on the Russian village of Nijni Karmadon in September 2010.
– Salang Avalanches, Hindu Kush, Afghanistan. 17 avalanches buried more than 2 miles of highway and killed nearly 172 people in February of 2010. These were triggered by heavy winds and rain and began at the southern approaches of the Salang Pass in the Hindu Kush Mountain range.
Predicting and preventing an avalanche
Experts and scientists try to predict when an avalanche is going to occur using historical data, weather information and data on the actual snow on a mountainside. However, it’s still not possible to predict with 100% certainty when and where they will occur.
One of the most effective ways to prevent an avalanche is to simply cause one. Avalanches can be triggered deliberately in order to prevent the snow building up.
Snow during an avalanche can reach speeds up to 80 MPH.
The peak, or most common periods that avalanches occur are during the period of December through March.
Avalanches are most common around Europe and North America. China and Indonesia also experience lots of avalanches and landslides. Avalanches are generally most common where a slope is around 30-45 degrees.
Surviving an avalanche depends on rescue speed and burial depth. The chances of survival are significantly higher if a victim is rescued within the first 15-30 minutes. Beyond 30 minutes, survival rates drop dramatically. Additionally, the severity of injuries and the depth of snow burial play a crucial role in determining a victim’s likelihood of survival.
Avalanches claim more than 150 lives worldwide each year. This number expected to rise as climate change increases their frequency and intensity.
An avalanche can reach speeds up to 80 MPH.
The peak period for avalanches is typically between December and March, when snowfall is heaviest and conditions create unstable snowpacks.