Natural Disasters



What is an Avalanche? An avalanche is simply a quick flow of snow down a slope. This happens in a starting zone when the forces on the snow are too heavy for its foundation.


What is an Avalanche?


One of the worst positions to find yourself is being stuck in an avalanche. Death is a very likely factor when you are entrapped in a snow slide. 90 percent these unfortunate events occur when a human is on a mountain with snow either skiing, snowboarding, or snowmobiling so this is something to consider the next time you decide to do any snow activities.

An avalanche is simply a quick flow of snow down a slope. This happens in a starting zone when the forces on the snow are too heavy for its foundation. The lower they get down the slope, the more they grow in mass because it is accumulating more snow as it goes downhill.

Avalanche Contents

Even though a snow slide is usually composed of air and snow, it can accumulate much more things going downhill such as ice, rocks, trees, and pretty much anything else on the slope making it extremely dangerous for travelers on the mountain that are caught in it.

When Do Occur and How Often?

Avalanches are not rare or random events that occur once in any particular area. They usually happen during winter or spring but movements in the glacier can cause avalanches at any given time. In mountainous terrain, snow slides are one of the most dangerous natural hazards to life and property because they are able to destroy almost anything in its way with an immense amount of snow at high speeds.

snowslide facts

Avalanche Facts and Information

Ten Deadliest Avalanches in History


  • In January of 1954, Blons, Austria saw one of its worst avalanches to date. 118 people were buried. While rescue workers were trying to get them out, another unexpected avalanche came and wiped them out.


  • In World War II, the Italian and Austrian military had bases in the Alps. On what is now known as “White Friday”, the Alps witnessed a series of avalanches claiming the lives of 10,000 soldiers, none of which guessed that enemy fire or bombs would be the least of their worries.


  • One of the most Ironic cases is the one that took place in Wellington, Washington on 1910. Three trains that were carrying 119 people were delayed at a station house so that they didn’t have to travel in poor weather. Unfortunately, an avalanche defeated the whole purpose of the stop when it swept the trains over a 150-foot cliff.


  • In 1970, Mount Huascaran was devastated by rock ice and snow cascading swiftly which caused 80,000 people to die and left around one million people homeless.


  • In the Rhone Valley of Switzerland and France, in 1720 the Galen Avalanche took 88 lives and 100 buildings. This avalanche caused numerous fires that led to the destruction of the town.


  • In 1618 on September 4, The Rodi Avalanche in Switzerland ripped through an entire city burying 2,500 people alive. No one survived the avalanche, however, 4 people who were away returned home only to find their entire community, homes, and friends destroyed.


  • The famous “Winter of Terror” which plagued the Swiss-Austrian Alps in 1950-1951 consisted of almost 650 sub-avalanches that claimed 265 lives. These events were caused by warm air currents combining with polar air currents, causing much more precipitation than the area could manage.


  • Instigated by blizzard conditions of wind and snow, the Lehaul Valley Avalanche in the Himalayas buried 200 people under 20 feet of snow in 1979. This was the only avalanche in the Himalayas to make it to the top ten list of most dangerous avalanches in the world.


  • Leaving only 50 people alive, the avalanche in Ranrahirca, Peru happened several years before the Great Peruvian Earthquake. Snow, mud, rock, and frozen debris fell down from Mount Huascaran smothering the whole village of Ranrahirca, leaving over 2,700 people dead and destroying every house in its path.


  • In 1965, construction on the Mattmark Dam, which is the biggest dam on earth, caused 12 men to lose their lives. A part of the Allalin Glacier broke off and fell onto the building site destroying everything in its path.


Natural Causes of Avalanches

Even though humans usually instigate avalanches, they obviously happen other ways as well. They can happen when there is an increased load of snowfall. Melting from solar radiation is another natural way that avalanches happen. Rain, icefall, rock fall, earthquakes trigger avalanches as well, depending on the circumstances. It is always important that you pay attention to weather reports if you are planning on doing any snow activities where there is a possibility that an avalanche can occur.

Different Types of Avalanches

There are different avalanches that are categorized by the characteristics of the avalanche. Knowing what areas are prone to certain types of avalanches can be helpful when planning to go on a ski trip or any activity involving being on a mountain with snow.

Loose Snow Avalanches

Loose snow avalanches are common in steep terrains. They usually occur in snow that has just fallen. Also, they can happen in old surface snow that was moistened by heavy solar radiation. Loose snow avalanches usually start at the point of the slope and widens as it travels downhill, using more snow. It resembles a teardrop, and large loose snow avalanches can result in slab avalanches.

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Snowslide in Switzerland

Slab Avalanches

Slab avalanches are formed when snow is deposited, or re-deposited by wind factor. They look like a block of snow cut out from its environment by fractures. These slab avalanches vary in thickness. They can be from a few centimeters to a few meters. Slab avalanches cause 90 percent of avalanche-related fatalities.

Powder Snow Avalanches

Powder snow avalanches form currents of turbulent suspension, in which they are the largest. This is a cloud of powder that lies over an avalanche that is dense. These form from any type of initiation structure or snow, but most of the time happens with dry, fresh powder. These types of avalanches can go move faster than 300km/h carrying a mass of 10 million tones. They can also travel long distances on a flat surface and uphill for a short amount of time.

Wet Snow Avalanches

Wet snow avalanches tend to be low in velocity suspension and consist of water and snow. The low speeds are caused by friction between the sliding surface of the track and saturated water flow. Although these types of avalanches tend to move slowly, they can still cause great damage with powerful destructive forces because of its large mass and density. Wet snow avalanches can consume boulders, earth, trees and other things in its path. These avalanches can be triggered by loose snow releases, or slab releases occurring only in snow packs that are saturated by water and equilibrated isothermally to the melting point of water. These types of avalanches usually happen towards the end of a winter season, when there is an immense amount of daytime warming.

In the end, any of the above avalanches could cause you to lose your life. With that being said, when you are out on the slopes trying to catch major footage, keep in mind that if a mountain is feeling too much pressure, you could be making your final recording.


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