What is Snow Immersion Suffocation (SIS)?

When you’re somewhere as beautiful as Mammoth Lakes it can be easy to throw caution to the wind in favor of fun. That’s especially true when you’re enjoying a powder day at Mammoth Mountain.

However, during deep snow conditions you need to be aware of snow immersion suffocation.

Snow immersion suffocation (SIS) is a serious danger to skiers and snowboarders, so the Mammoth Bound team has created a short guide to what it is and how to avoid it. Check it out below, then use Mammoth Bound to find the best deals on ski and snowboard rentals in Mammoth Lakes!

SIS and Tree Wells

One of the most dangerous types of SIS are tree wells.

On a typical slope, powder snow falls on harder snow that has consolidated into a solid base so that you can fall through the powder, hit the base, and go no further down. When heavy snow falls around a tree with low lying branches, like an evergreen tree, the branches prevent the wind and sun from forcing the snow to consolidate into a solid base.

As the snow around the tree compacts, the snow around the base remains powder, forming a well full of powdery snow. If you fall into the well headfirst, then there is a serious chance that you will not be able to get out and the powder will block your airways, causing you to suffocate.

SIS can happen away from trees too, but it will not happen on groomed runs where the snow has formed a solid base.

How to Avoid SIS

The easiest way to avoid SIS is to not leave the groomed runs at a resort. However, we know that the best skiing is snowboarding is often away from groomed runs.

If you do leave the groomed trails then do so with a partner, and make sure your skiing and snowboarding skills are good enough to stay in control on ungroomed runs.

Don’t think that just because you can stay in control that you can avoid tree wells and SIS though. Tree wells can form around small trees where you don’t expect them, and there’s always a chance you lose control while skiing and snowboarding. 

What to do if You Fall in a Tree Well

Tree wells are extremely difficult to climb out of on your own, so if you fall into one then there’s a good chance you’ll be there for awhile.

Protect yourself by first doing everything you can to keep your head above the snow. You don’t want to struggle and dig yourself deeper in though, so don’t panic and thrash. Use the tree trunk or branches to pull yourself up if possible.

Next you need to get someone’s attention by either yelling or blowing a whistle to call for help. Ideally this would be your partner, but if you’re alone or no help comes and you can reach your phone then call the mountain’s emergency services for an emergency rescue.

Leave a Reply

Your email address will not be published. Required fields are marked *

Scroll to top