If you love snowboarding or to ski on the snow, then the idea of an avalanche forming behind you will always be an idea at the back of your mind.
It is a feeling that you cannot shake off even if you try.
Between the years 2017 to 2018, there were 22 reported accidents and 25 fatalities.
Avalanches are a reality especially if you decide to ski in high-risk zones.
Did you know that it is not that hard to prevent most cases of being a victim to an avalanche?
In this article, I am going to show you all the ins and outs of an avalanche. It will include information such as how it forms, the types you can find and also how they are triggered.
I will also reveal some of the preventative measures that ski resorts take to prevent massive avalanches and also what you can do to avoid it.
Lastly, I will also give you some tips that you can follow when facing an avalanche and also what to do once you are buried under the snow.
These natural disasters are severe and should not be taken lightly.
Are you ready?
What Is An Avalanche?
An avalanche is a mass of snow that will fall down a slope. It can range from smaller masses such as sluffs up to slab avalanches which can destroy houses and flip cars.
In this section, you will learn more about the requirements needed for an avalanche to exist and also the types of avalanches you can find.
For an avalanche to occur, there must be a snowpack present at a specific angle. Many factors will contribute to the formation of a snowpack.
The angle at which the snowpack is forming will also contribute significantly to the accumulation and triggering of the snowpack to create an avalanche.
- The temperature must be stable. When temperature fluctuates, some of the snow will melt and then freeze again which will cause it to be more solid and stable so that it can accumulate on steeper slopes. When the temperature is more stable and between a narrow range, the snow will be softer and can only gather on shallower angles.
- The angle of the slope. For an avalanche to happen, it needs to build up enough snow which can be triggered. For this to happen, the snow needs to accumulate at a specific angle. The angle needs to be shallow enough for the snow to build up and also steep enough for it to build up speed. There is not a set angle for an avalanche occur, but rather a range. Most avalanches occur at between the angles 35 to 45 degrees. Any angle lower than 25 degrees will allow for snow to build up, but it will not allow it to tumble. An angle steeper than 60 degrees is too steep which will not allow for enough snow to accumulate.
- The rate of the snowfall. If the snow is falling at a slow pace, the snow particle will have enough time to bond with each other and create a more stable snowpack. If the snow is falling more rapidly, there will not be enough time for the new layer of snow to bond with the existing layer thus creating instability.
- The wind must be strong enough. If the wind is strong enough, it can help move snow to form potential snowpacks on areas where there is a slope. The softer type snow that was established at more stable and higher temperatures will be more susceptible to the wind blowing. If the snow manages to land on an existing snowpack that is not stable, then it might trigger an avalanche.
- Rainfall intensity. If there is a light rainfall, the water will slowly drain through the snow which will allow it to form a layer of ice if the temperature is low enough. This ice layer will strengthen the snowpack. If there is heavy rainfall, the water will drain through the snow more rapidly which will make the snowpack more slippery because there is not enough time for the water to freeze.
- The layered structure. The layered structure of the snowpack is a determining factor in the type of avalanche (will discuss the types later). For instance, a slab avalanche needs a thick and stable layer that was formed upon an unstable layer. Loosely packed layers from powdered snow will also create an unstable layer which will be more prone to an avalanche. Another factor is the structure of the crystals. For example, six-pointed crystals can interlock with each other which creates more friction between the layers. There is also a temperature gradient between the layers which can influence its stability.
Avalanche Phases And Triggers
An avalanche has a starting point, a track and also a runout. These are the three phases an avalanche will go through. I am also going to discuss some of the triggers that can stimulate an avalanche.
- Starting point. The starting point of an avalanche must have a slope that is shallow enough for the snowpack to form and steep enough for it to accelerate. Most avalanches start near the ridge that consists of a chain of mountains that are connected. It is in this area where the slab must break free from the rest.
- The avalanche track. It is the path to which the avalanche will follow as long as there is a slope steep enough. The most common indicator of a slope is a forest clearing. If you should see a forest clearing in front of a large mountain slope, then you should avoid this area in the winter. You do not want to spend too much time on an avalanche track as avalanches tend to recur at the same area.
- Endpoint (the runout). The endpoint or runout is where the avalanche eventually stops. Indicators of a runout is a lot of dead trees and debris which was carried along by the avalanche.
- How it is triggered. Most avalanches are triggered when the snowpack becomes under stress and cannot hold itself together. The stress can gradually increase to the point where it breaks, or it can happen in an instant. Some avalanches are triggered by humans where it also consists of 92% of accidents. Heavy snowfall can add too much weight to the snowpack where it will break. Heavy rains and wind can also put enough stress on the snowpack making it unstable.
Types Of Avalanches
In this section, I will explain more about the types of avalanches. Each type might have a different cause and appearance.
This type of avalanche is probably the deadliest of them all. They happen when a large section of consolidated snow break away from the mountain.
They also account for the majority of fatalities. These large slabs also travel at a breakneck speed of more than 70 miles per hour.
The size of the slap can range from a couple of meters up to almost the size of a football field. This avalanche forms when there is a thick layer of consolidated snow forms on top of a weak layer that is unstable.The video above is a clear example of a slab avalanche.
Snow powder avalanches
These types of avalanches are less dense than slab avalanches but can also be deadly. They have a cloud-like appearance when they move and are on top of another snow layer.
The clouds can also move in waves that will repeat itself until it reaches the runout.
The closer the cloud comes to the runout, the denser it becomes. It is these types of avalanches that bury its victims under the snow. They might appear light and fluffy but can soon become as solid as concrete when it halts.
Sluffs (loose snow avalanche)
This type of avalanche is not as dangerous as the previous two mentioned but can still pose a danger. I would say that the snow released by this avalanche is denser than snow powder avalanches and is less dense than slab avalanches.
They typically happen when a small mass of snow is loosened from the top of a ridge where it starts to run down. They are also much smaller than the previous two mentioned.
A wet avalanche happens when water caused by rain or snow melting by the sun breaks the cohesion that holds the snow together. Its traveling speed is not that high, but the mass that comes with it is considerable.
They can cause severe damage to a building and is like a tsunami of wet cement that is heading your way. They result in larger chunks of snow that will flow down the slope.
You can also imagine a front loader downing a full load of slush puppy on you which is similar to a wet avalanche.
How To Avoid An Avalanche
There are some signs and tests that you can look for to ensure that you are not skiing on a snowpack that is unstable. You can look at the danger scale, forecast or dig a quick pit where you will perform a compression test.
Avalanche Risk And Danger Scale
This scale indicates five levels of danger that you need to be aware of. Usually, you will find these signs on the routes inside snow resorts which will warn the guests.
This scale is categorized according to the stability of the snowpack and the frequency of avalanches in that area.
Heavy rains and widely fluctuating temperatures are high-risk indicators for the triggering of avalanches. Check the weather forecast in your ski area to have a better idea of the risks involved.
You can also visit one of the guides inside the resorts which will warn you of any upcoming potential events that have increased the risk.
Dig A Quick Pit
You will often see a resort guide or professional skiers that will dig a large and deep hole into the snow. They do this to evaluate the layers of the snowpack.
They will cut out a slab of snow to perform a compression test to see how consolidated the layers are.
The can do this for an entire slab or each layer. You can do it with your fist or with the help of a shovel. Each layer needs to be consolidated.
You do not want to ski on a slope where the top layers are consolidated while the bottom layer is not. It will result in a slab avalanche. They also look at the grain of the snow.
The tactics listed below are used by ski resorts to limit the formation of large avalanches by triggering smaller ones to prevent them from developing further.
They might use explosives or stability testing methods such as slope cuts to trigger smaller potential avalanches. Artificial barriers can also be used to limit the build-up of snow at specific areas.
Create Artificial Barriers
During summer times some ski resorts will install snow fences at high-risk areas for avalanches. These fences will help to keep the snow at bay and prevent massive build-up in sensitive areas. It will also stop the wind from blowing the snow on these areas.
There is also the possibility to plant trees at some of these areas which will also stop unstable snow layers from forming. Sometimes trees can also stop an avalanche in its tracks and preventing it from going further.
Explosives are used to trigger smaller avalanches to prevent larger ones from forming over time. The explosives can be manually planted or dropped by a helicopter.
Ski patrols can also use radar to identify weak areas and then trigger these areas with explosives. Mortars have also been used to trigger smaller avalanches.Sometimes after a heavy snowfall, tests will be done to determine newly formed areas that are unstable which will require an explosive.
Here is an article on Tamarack resort where they use explosives to prevent larger avalanches after 17 inches of snowfall in one day.
Stability testing is performed by experienced skiers who deliberately ski over a high-risk starting zone to trigger a small avalanche.
This process is called “ski cuts” or “slope cuts.” Skiers will not go straight down a high-risk area but rather over the starting point at an angle so that they can get out of avalanches path once it is triggered.
Snowmobiles can also be used. This process works well for triggering smaller avalanches rather than bigger ones.
It is even harder to trigger larger avalanches because it requires more pressure and weight to trigger them. The skier’s weight is usually not enough to trigger the bigger avalanches.
How To Survive An Avalanche
Know, you know what to do to avoid an avalanche, but sometimes you might not be so lucky. In this section, I will show you how to prepare for one and also what to do if one is heading your way. You will also learn what to do once you are buried underneath the snow.
- Wear safety gear. Most fatal injuries result from heavy hits to the head. You can significantly reduce the risk of head injury by wearing a helmet. If you are skiing, then it is detrimental to wear a helmet to prevent heavy knocks on the head. You can also wear elbow and knee guards to protect these delicate areas. There is no gear that I know of that can prevent your ribs from breaking.
- Carry a beacon and a probe. You never know when an avalanche might bury you under the snow. How will the rescue team find your location if they cannot see you? You can make it easier for them by wearing an avalanche beacon which will pinpoint your location. These beacons come in the form of a small radio that you can carry with you. You can also use an avalanche probe which you can use to break the snow from below to pinpoint your location.
- Wear an ABS backpack. These backpacks are like regular backpacks with airbags in them. They offer the same benefits like a car with airbags. You can activate airbags by pulling the trigger which will allow them to inflate. The bags will also help you to stay on top of the avalanche. It will also lessen some of the impacts that you can receive from an avalanche.
The video above will show you how this backpack has saved a man’s life during an avalanche.
When An Avalanche Is Approaching
- Avoid triggering an avalanche. Sometimes when walking on the ridge of a snowy mountain, you can potentially trigger an avalanche. If you feel the snow giving in underneath you, you can jump off the slope in the opposite direction.
- Regarding ski equipment and snowmobiles. If you are skiing down a slope, or you are driving on a snowmobile, and you spot an upcoming avalanche, try to get off its path. If it is already too late, you should abandon your ski equipment and snowmobile. It can drag you down further along the avalanches, and it can also roll over you. With skis, you even pose the risk of tearing the ligaments of your ankle.
- Get out of the way. When you spot an approaching avalanche, you should get out of its path as fast as possible. Do not waste any time and if you are carrying heavy equipment, you should drop it to move faster and lighter. However, you should not discard your receiver or probe as it might save your life.
- Hold on to a tree. By grabbing onto a nearby tree, you will reduce the risk of the avalanche pulling you with it. You might still be vulnerable to some of the debris the avalanche might carry with it, but at least, it will not bury you under the snow.
If You Get Caught
- Move to the top. When the avalanche has hit you, the best thing that you can do is to move your arms and legs in a swimming motion to stay on top of it. Try to lie on your back if possible so that your face is not exposed. This needs to be done aggressively to avoid being buried under the snow.
- Create an air pocket. The worst has passed, and the snow has come to a standstill. The only problem is that you are buried underneath the snow. The first thing that you want to do is to create an air pocket near your face so that you have room to breathe. You can use your face or one of your hands to do this. Try to pull your head upwards and use your chin to create the air pocket. Conserving energy and air at this point is essential. You should also try to use one of your arms or the avalanche probe to stick it through to the surface.
Now you know more about avalanches than the average person. You can use this knowledge to prevent and also survive an avalanche.
Have you ever fallen victim to an avalanche?
Please leave a comment below and tell us how it went.