Types And Causes Of Avalanche


Types And Causes Of Avalanche

Spending winters in the mountains with nothing but white snow on all sides can be quite relaxing. For those wanting an adrenaline rush, the snow is a great place to go skiing, snowboarding and even having snowball fights. However, being on the slopes means one has to constantly be alert if they don’t want to get caught in an avalanche. The rapid descent of snow may seem harmless, but it can cause a lot of damage to life and property. This is why understanding of avalanches is necessary for those fond of spending their luxury time in the mountains.

On any slope, the snow is piled up and supported by a snow-pack. It keeps the snow from tumbling down all the time. Avalanches occur when the snow-pack starts to weaken and allows the buildup of snow to be released. Small avalanches are generally made up of ice, snow and air. The larger ones comprise of rocks, trees, debris and even mud that is resting on the lower slopes. Contrary to belief, these snow slides are not random events that occur without any warning signs. Winter season is when they are most common, often brought on after a large storm in the area. Rainfall and sleet also tend to be responsible for avalanches in the summer and monsoon season.

Types And Causes Of Avalanche
Types And Causes Of Avalanche

Types Of Avalanche

1.Loose Snow Avalanches: First of these are the Loose Snow Avalanches. They are common on steep slopes and are seen after a fresh snowfall. Since the snow does not have time to settle down fully or has been made loose by sunlight, the snow-pack is not very solid. Such avalanches have a single point of origin, from where they widen as they travel down the slope.

2. Slab Avalanches:  Loose Snow Avalanches in turn could cause a Slab Avalanche, which are characterized by a the fall of a large block of ice down the slopes. Thin slabs cause fairly small amounts of damage, while the thick ones are responsible for many fatalities.

3. Powder Snow Avalanches: Powder Snow Avalanches are a mix of the other forms, Loose Snow and Slab. The bottom half of this avalanche consists of a slab or a dense concentration of snow, ice and air. Above this is a cloud of powdered snow, which can snowball into a larger avalanche as it progresses down the slope. The speed attained by this avalanche can cross 190 miles per hour and they can cross large distances.

4. Wet Snow Avalanches: Finally, there are Wet Snow Avalanches. These are quite dangerous as they travel slowly due to friction, which collects debris from the path fairly easily. The avalanche comprises of water and snow at the beginning, but an understanding of avalanches has shown us that it can pick up speed with ease.

Types And Causes Of Avalanche
Types And Causes Of Avalanche

Causes Of Avalanche

Snowstorm And Wind Direction: 

Heavy snowstorms are more likely to cause Avalanches. The 24 hours after a storm are considered to be the most critical. Wind normally blows from one side of the slope of mountain to another side. While blowing up, it will scour snow off the surface which can overhang a mountain.

Heavy Snowfall

Heavy snowfall is the first, since it deposits snow in unstable areas and puts pressure on the snow-pack. Precipitation during the summer months is the leading cause of wet snow avalanches.

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