When snow builds up there is always a risk of it sliding down a mountainside.
Especially if the conditions are right.
The angle of the slope, the amount of snow, and a trigger.
That’s all it takes for an avalanche to take place.
So which types of avalanche are the most dangerous ?
Lets first have a quick look at the main different types of avalanche.
Slush avalanche
At the start of the season the snow starts to fall, it sticks on the ground and you think brilliant here we go.
The weather warms slightly and there is rain instead of snow.
As the snow gets saturated with water it starts to turn to liquid and slides down the mountainside.
This is similar to a mudslide, where the rain will turn the mud into a thick river.
These are dangerous avalanches as they have little or no air pockets in them.
When they come to rest it is almost a solid mass of icy water or slush.
They do occasionally happen when you get unseasonally warm rain during the skiing season, but normally are restricted to the start and end of the season when the weather warms and the rains start.
Slab avalanches
The snow starts to build over the season and with the changing weather conditions you get changing surface conditions of the snowpack.
These surface conditions get buried under new snow and compressed.
If you get an icy layer covered with new snow the two don’t stick to each other well and when there is enough new snow, and a slope at the right angle and a trigger.
A whole slab of snow can break from the snowpack and slide down the mountainside.
The slab will break up as it cascades at terrifying speeds.
The energy in these avalanches is massive and anything caught in the way will be taken with it.
it is not only storms that can crate the amount of new snow in an area ,the wind can move snow from one place to another.
This wind buildup can create areas which are very likely to have an avalanche, so looking at a ride which looks perfect and jumping on it may be the trigger required for the ride of your life.
Rocky slopes which look like there should be avalanches may be very stable as the rocks form natural avalanche protection. But don’t rely upon this as the upper layers of the snow pack can become unstable and shear.
If the avalanche ends up in open countryside there is little end energy.
If, however, the end zone is in a valley then the amount of snow and the speed of the avalanche can cause the snow to compact very densely, almost like concrete.
Very difficult to dig, or probe.
If you are caught in one of these, trying to ski out maybe impossible due to the size and speed of the slab.
Sluff avalanches
Sluff or loose snow avalanches are caused by the new dry snow moving down the mountain.
New loose snow can build up from storms or can be moved by the wind.
Given certain slope conditions the new snow doesn’t stick very well and when it builds up then it will suddenly release and cascade down the slope.
It can build up a large cloud or just slip down looking like water.
When skiing on loose snow you will probably cause a few sluffs.
As long as these are small then everything is ok, it is when that buildup it too great and a mass of loose snow decides that it needs to be someplace else that problems can occur.
The main danger from a sluff avalanche is being taken over a cliff.
Sluff avalanches are less compressed than slab or slush avalanches, so are easier to dig and if caught in one you can generally thrash around to make a pocket of air.
So which is the most dangerous
The slush avalanche is the most dangerous, but most people are not skiing at the point when the snowpack turns into slush either at the start or the end of the season.
If there is an unseasonable warm spell with a lot of rain rather than snow this is something to bear in mind.
But a very close second and one which does kill a lot of people going off into the back country is the slab avalanche.
Without being able to identify the typical avalanche sites and knowing the weather from not only today but up to a week ago then you are putting yourself at risk.
This mass of snow will sweep everything out of its path and bury anything under its bulk.
If you are caught up in it and it crashes through trees , then you may sustain injuries when being swept along with it.
A lot of people are rescued from the avalanche only to perish from trauma injuries sustained in the avalanche.
The sluff avalanche has little power, unless very large and as I said you usually cause small ones as you are riding the soft dry new snow.
So once you are down at the end of the ride, move out of the path of any loose falling snow.
How to minimize your risk
Get trained if you are thinking of going into the back country, and make sure your buddies who go along are also trained.
Think to yourself – would you rely on them to get you out in an emergency – if yes then ok, if no- think twice about going with them.
Carry the right kit.
This at a minimum is a beacon, probe and shovel an preferably a radio link.
This way you can help others out or be rescued if necessary.
Have a look around at the info on the site to get familiar with the kit, there are plenty of review on hear and more being added.
Learn to spot the signs of an avalanche, keep an eye on the weather and the snowpack.
And practice, practice, practice
Watch for buildups in snow via the wind and ride safe.
There is always another ride to slide but you only have one life.