Snow Cracks: the dangers, how to spot them, and what to do if someone falls in one.

Previously we made an Instagram of our friend who had fallen into a snow crack whilst skiing in the Niseko area:

James fell whilst traversing the top of the slope and tumbled down. He was fine from his fall but when he tried to stand up - his feet completely disappeared underneath him. My Go Pro was still filming so later we found this still image.

This type of crack is called a 'Glide Crack'.

So, what is a 'Glide Crack'?

A glide crack appears when the snowpack slides slowly downhill at different rates, faster towards the bottom. Often the movement is just a few mm per day. The snowpack below the glide crack may release suddenly, giving rise to a full depth avalanche.

Why are they so common in Niseko in particular?

There are 3 main factors contributing to this:

1. We get LOTS of snow

2. Due to the low altitude we have intense solar radiation

3. Underneath the snowpack in lots of places is an abundance of sassa grass.

Niseko has a very low altitude and as such is much more susceptible to the effects of solar radiation. This means that when the sun is out the snow consolidates rapidly, which can lead to tension in the snow pack - causing these cracks to appear. Often Glide cracks occur on convex rolls where the effect of gravity is a lot higher on the lower section than the upper section.

Beneath a lot of the snow here in Niseko is incredible amounts of sassa (bamboo), which can struggle to withold the heavy weight of the snow and is unable to support it. Combining the sassa with the solar radiation makes these the two main factors which makes cracks so common here in Niseko.

The cracks themselves can be very difficult to spot from above, and if there is considerable snowfall (which we often receive from the snowgods here) and/or wind, they can be covered up easily. The best way to avoid them is to find out where they are usually formed. You can do this by asking Ski Patrol or local guides in the area.

This video shows just how easy it can be not to see one: https://www.youtube.com/watch?v=qTZVVLTxMBE

Apart from being incredibly scary, what are the dangers of falling into a 'Glide Crack'?

The biggest danger is:

1. Getting injured upon falling into a crack - ride with buddies so they can help you get out of any tricky situations, and ALWAYS wear your helmet!

These cracks can also lead to slab avalanches where you have the risk of dying of asphyxiation. This is the process of being deprived of oxygen, which can result in unconsciousness or death; suffocation.

How can you avoid falling into a 'Glide Crack'?

This can be tricky as they are hard to spot

Know the area you’re skiing. If possible, look at the pitch from a chairlift and scope it out. Talk to the ski patrol or people you know that may have skied there recently and gauge if there are any dangers.
Refrain from skiing south facing slopes on days where there is an increase in temperature, and for a few days after as the sun will affect these slopes the most.
Often the cracks are smaller than the length of skis, so sometimes you can ski across or jump across them.
Ski using a buddy system: ski a pitch of just a few turns using a lead and sweep. Ideal group size is 3-5. Always stay within visual range, and if you loose visual contact at no point lose aural contact… If you do, move incredibly careful until you resume contact. Have a plan of your line, use anchor points and have a good idea of potential escape points.
Read the avalanche report every day before skiing. Here are 2 options for the Niseko area: http://niseko.nadare.info/ http://www.skijapan.com/niseko-snow-report/
Hire a ski guide to take you into the backcountry who knows the area well.

What to do if you or your friend falls into a 'Glide Crack’

IN ALL CASES REMAIN CALM!

If you have fallen in a glide crack:

Rapid movement and struggling will compact more snow around you and worsen your situation. Save your energy and think calmly.

Use your poles, skis or board to stabilize yourself and prevent you from falling any deeper. Talk with your riding buddies and let them know what kind of position you are in and how they can help without worsening the situation.

If you have fallen head first look for air pockets to push your head into gently. If you think you might be able to get out by yourself, turn your body as slowly as you can to turn yourself upright.

Try and exit the crack from the side, not directly from where you fell.

You can also dig in your skis across the crack and use them as steps to get out.

Call ski patrol for help. They need to know the area you're in, altitude, aspect, no of members in the group, the situation, how long have they been in there, on skis or board, any medical info, visual or aural contact.

If your friend has fallen in a snow crack:

Assess the situation...

See if your friend can get out by themselves.

Ensure that you don't ski down to them directly above them. Make sure that no other skiers ski down above them. You don't want to cover them in snow.

Use a rope to tie around your friend so you can A) help them out or B) ensure that they fall no further whilst trying to exit the crack themselves.

Call ski patrol for help. They need to know the area, altitude, aspect, no of members in the group, the situation, how long have they been in there, on skis or board, any medical info, visual or aural contact.