What is a Tree Well and Snow Immersion Suffocation (SIS) Accident?

Information provided by, deepsnowsafety.org

Tree well/ snow immersion suffocation accident can happen when a skier or snowboarder falls – usually headfirst – into a tree well or deep loose snow and becomes immobilized and trapped under the snow and suffocates.

In an inverted position you can become trapped under the snow. Breathing becomes difficult as the loose snow packs in around you. Without immediate help from your partner, you may suffocate.

Prevention of falling into a tree well or areas of deep snow is all-important because the odds of surviving deep snow immersion are low.

90% of people involved in Tree Well/ SIS hazard research experiments could NOT rescue themselves. If a partner is not there for immediate rescue, the skier or rider may die very quickly from suffocation – in many cases, he or she can die as quickly as someone can drown in water.

Tree wells have accounted for 20% of ski area fatalities of all kinds.

What if you go down?

Yell or use whistle to get your partners attention.
Do whatever you can to keep your head above the surface of the snow including rolling, grabbing tree branches or the tree trunk. If possible, keep your feet below level of your head.
If you become immersed, make a space around your face and protect your airway – resist the urge to struggle, it could compromise your airspace and entrap you further.
Stay calm to conserve air.
Trust your partner is on their way.
If possible, use your cell phone to call ski patrol or the resort’s emergency number.

What if your partner goes down?

More than half of all SIS victims were with partners that did not see them go down. Lose sight of your partner and you could lose your friend.

If you lose contact with your partner, assume they need help. Many SIS victims have died while their partners were waiting at the bottom of a lift.

TIP: In dense tree areas or in poor visibility, ski or ride short pitches and stop to regroup often – stay within sight of your partner!

Don’t leave to get help – Stay with your partner!
Call for additional resources. Use a whistle or yell for assistance. If possible, call ski partol or the resort’s emergency phone number.
Evaluate scene safety for yourself.
IMMEDIATELY begin snow immersion rescue efforts. – Go directly for the airway, and keep it clear, be careful not to knock more snow into the hole. Clear any snow from the airway and continue necessary first aid or extrication efforts
Do not try to pull victim out the way they fell in. Instead, determine where the head is and tunnel in from the side. – When tunneling directly for the airway be careful not to knock more snow into the hole.Continue expanding the tunnel to the airway until you can extricate the body. Efficient “strategic shoveling techniques”with multiple rescuers is very useful.