Key takeaways
- A tree well is a hidden pocket of loose, deep snow around a tree's base.
- Falling in (often headfirst) can trap a rider and cause snow immersion suffocation (SIS).
- The danger is greatest in deep, fresh snow among evergreens; most victims can't self-rescue.
- Stay safe: ski trees with a partner in sight/voice contact, and know self- and partner-rescue steps.
This is general educational information, not a substitute for hands-on snow safety training. Get proper instruction before skiing deep snow and trees.
What a tree well is
A tree well is a void or pocket of loose, deep, unconsolidated snow that forms around the base of a tree. The tree’s lower branches keep snow from packing down near the trunk, and in deep snow those same branches hide the well from view — creating a trap a skier or rider can fall straight into, frequently headfirst.
Why they’re deadly
Fall into a tree well and the loose snow collapses around you, often pinning you upside down where struggling only sinks you deeper. This causes snow immersion suffocation (SIS), which can be fatal within minutes. Studies and resort safety programs stress that most people who fall into a tree well cannot get out by themselves.
Skiing powder in the trees, two partners ride one at a time and stop within sight and earshot at each pitch — so if one vanishes into a tree well, the other is close enough to reach them and dig immediately, before suffocation sets in.
Staying safe
Ski trees and deep snow with a partner, never alone, keeping each other in constant sight and voice contact. If you fall in, try to keep your head up, make an air pocket, and avoid thrashing deeper. The hazard rises in fresh, deep powder and accompanies off-piste and backcountry skiing alongside avalanche risk.
The bottom line
A tree well is one of the most underappreciated killers in deep snow: a hidden void around a tree that can trap a fallen rider headfirst and suffocate them within minutes. The defense is simple but vital — never ski powder and trees alone, keep your partner in sight and voice contact, and know the rescue steps before you need them.
Frequently asked questions
What is a tree well?
A tree well is a hole or pocket of loose, deep snow that forms around the base of a tree, where the branches prevent snow from packing down. In deep-snow conditions it's hidden by the tree's lower branches, creating a trap a skier or rider can fall into, often headfirst.
Why are tree wells dangerous?
If you fall into a tree well, the loose snow can collapse around you and trap you — frequently upside down — making it nearly impossible to escape on your own. This can lead to snow immersion suffocation (SIS), which can be fatal within minutes. Most victims who fall in cannot self-rescue, which is why partners matter.
How do you stay safe from tree wells?
Ski or ride trees with a partner, staying within sight and voice contact and stopping where you can see each other — solo deep-snow tree skiing is the highest risk. If you fall in, try to keep your head up, create an air space, and resist struggling deeper; rescue depends on a partner reaching you fast, so never lose track of each other.
Sources
- Tree well & deep snow safety — The Mountaineers
- Snow safety awareness — Avalanche.org