An avalanche is any amount of snow sliding down a mountainside. It can be compared to a landslide, only with snow instead of earth. Another common term for avalanche is “snow slide”. As an avalanche becomes nearer to the bottom of the slope, it gains speed and power, this can cause even the smallest of snowslides to be a major disaster.
While avalanches are sudden, the warning signs are almost always numerous before they let loose. In 90 percent of avalanche incidents, the snow slides are triggered by the victim or someone in the victim’s party. Avalanches kill more than 180 people worldwide each year. Most are snowmobilers, skiers, and snowboarders.
Many avalanches are small slides of dry powdery snow that move as a formless mass; These account for a tiny fraction of the death and destruction. Disastrous avalanches occur when massive slabs of snow break loose from a mountainside and shatter like broken glass as they race downhill. These moving masses can reach speeds of 130 kilometers (80 miles) per hour under five seconds.
Avalanches are most common during and in the 24 hours right after a storm that dumps 30 centimeters (one foot) or more of fresh snow. The quick pileup overloads the underlying snowpack, which causes a weak layer beneath the slab to fracture. The layers are an archive of winter weather: Big dumps, drought, rain, a hard freeze, and more snow. How the layers bond often determines how easily one will weaken and cause a slide.
Storminess, temperature, wind, slope steepness and orientation, terrain, vegetation, and general snowpack conditions are all factors that influence whether and how a slope avalanches. Different combinations of these factors create low, moderate, considerable, and high avalanche hazards.
What to do if caught in an avalanche?
Reacting in the first few seconds trying to escape the area by jumping up or moving to the side of the avalanche and throwing away heavy equipment. If there is vegetation, try to hold on to a tree, shrub or something.
If you did not manage to avoid the avalanche, start “swimming” to remain as much at the surface as possible and not sink in as the human body is much denser than snow, so you will tend to sink as you get carried downhill. Swim on your back. This way your face is turned toward the surface, giving you a better chance of getting oxygen more quickly if you get buried. Swim uphill will get you closer to the surface of the snow.
How to survive if you get buried in snow?
Hold one arm straight above your head, pointing in the direction of the snow’s surface; it may help rescuers locate you. Spitting out a small amount of your saliva can also help with figuring out which way is up because the fluid will run down; same for pee if you are able to dig a pocket around your body. Once the avalanche stops the snow settles in as heavily as concrete. Dig an air pocket near your nose and mouth; with a small air pocket to breathe from, you should have enough air to last at least 30 minutes.