This quality tree well safety information is brought to you by deepsnowsafety.org.
1. What is a Tree Well and Snow Immersion Suffocation (SIS) Accident?
A 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.
2. What is a Tree Well?
A tree well is a void or depression that forms around the base of a tree can and contain a mix of low hanging branches, loose snow and air. Evergreen trees in particular (fir, hemlock, etc) can have large, deep tree wells that form when low hanging branches block snow from filling in and consolidating around the base of the tree. These voids can be hidden from view by the tree’s low hanging branches.
There is no easy way to identify if a particular tree has a dangerous tree well by sight therefore, treat all tree wells as dangerous.
In simple terms, a tree well is a hole or void in the deep snow, which is clearly marked by a tree. You can easily identify and avoid these areas.
The picture from the site of a fatal Tree Well/ SIS accident demonstrates that even very small trees with just their tops visible can be lethal.
|Mike standing in ungroomd treed area. (in black jacket & black helmet)||Mike (6’1″) Stepping into the tree well (in black jacket & black helmet)|
|Mike standing in ungroomd treed area. (in brightly colored orange jacket)||Mike (6’1″) Stepping into the tree well (in brightly colored orange jacket)|
3. Where do Accidents Happen?
Most all Tree Well/ SIS accidents happen in ungroomed terrain. A groomed run is a ski or snowboard run that has been driven on by a snow machine to compact and consolidate the snow.
- Most Tree Well/ SIS accidents happen where there are combinations of deep powder and trees and where lots of powder skiers and snowboarders are seeking powder snow.
- Lots of deep loose snow makes for the best powder skiing conditions. Unfortunately these conditions also significantly increase the chance of a Tree Well/ SIS accident.
- 70% of all Tree Well/ SIS accidents involve tree wells. Deep snow Tree Well/ SIS accidents occur in areas of deep snow, deep snow pockets or terrain that concentrates deep snow such as steep drops, and creek beds.
The risk of a Tree Well/ SIS accident is greatly reduced just by staying on groomed runs.
|Photo B – Tree 1 Tree Well|
|Photo A – Groomed vs. UngroomedSnow Cat creating groomed snow & Tree 1 in ungroomed area.|
|Gwyn (6′) stepping into tree well of same Tree1 that is in photo A in ungroomed area.|
|Photo C – Fatal Tree Well Site.|
|This small tree in ungroomed area was the site of a fatal tree well accident.|
4. When do Accidents Happen?
Most Tree Well/ SIS accidents have happened during or just after big snow storms or storm cycles. In general terms, the more fresh snow the higher the risk.
As of 2011 research, an average of four Tree Well/ SIS accidents happen each season in the United States.
See “SIS by the numbers section for more details”
5. 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.
6. Keep your partner in sight at all times!
What if your partner goes down.
|Volunteer Skier being Rescued by Ski Patrol During Tree Well Experiment.|
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.
|5.||Do not try to pull victim out the way they fell in. Instead, determine where the head is and tunnel in from the side.|
7. You can Prevent a SIS Accident
- The easiest was to avoid a SIS accident is to remain on groomed areas and avoid deep snow and tree well areas.
- Be aware of the recent snowfall and the depth of the loose snow – check local resources for recent snow conditions.
- If you venture into UNGROOMED terrain:
Please see Safety Equipment Notes section for details about each safety equipment item.
|4.||Keep your partner in sight at all times. In many SIS accidents, skiers and snowboarders, have part of their body or equipment visible – but a partner wasnt there to see them.|
|5.||Take heart. Increased awareness and education reduces SIS risks. There are more reported cases of skiers and boarders being rescued by their partners each season.|
8. Safety Equipment Notes
The type of equipment that can help in a SIS accident is readily available and is already being carried by skiers and snowboarders who regularly venture into backcountry/ avalanche terrain and many in-ski area riders.
8 thoughts on “Tree Well Suffocation Safety Information:”
Great Info !! years ago at AM after a big dump we skiing outer outer when my ski partner fell into one, backwards, I saw it out if the corner of my eye heard a loud “F*** ” and made a quick turn. thankfully i was able to grab his belt and yank him out about 15-30 seconds after he fell in – this was back in the days of medium width lengthy skis and his 195 Volkls kept him from going deeper in otherwise it would have been a fast descent to the lake view loading zone to get ski patrol (it was also long before cell phones). Now he doesn’t ski much – me …. I can’t get enough . hopefully this will be a concern soon enough in tahoe – there sure as heck isn’t any danger of that happening anywhere in Tahoe currently.