Ukucwiliswa emthonjeni wesihlahla (SIS) kanye nokusinda ekumitheni kweqhwa elijulile¶

A tree well (or Snow Immersion Suffocation / SIS hazard) is a hidden, unconsolidated void of loose snow, low-hanging branches, and air surrounding the trunk of a conifer tree after heavy snowfall. When a skier or snowboarder catches an edge near an evergreen tree and tumbles headfirst into this hidden pit, the surrounding curtain of dry powder snow collapses inward like quicksand while their skis or snowboard wedge into the branches above, trapping them upside down in total darkness. According to the Northwest Avalanche Center (NWAC) and the National Ski Areas Association (NSAA) in the United States and Canada, non-avalanche Snow Immersion Suffocation accounts for roughly 20 to 25 percent of all in-bounds winter sports fatalities during deep powder seasons, and in survival experiments, 90 percent of volunteers placed into a tree well could not rescue themselves without a partner standing right outside the tree.

This guide walks skiers, snowboarders, snowshoers, and backcountry riders through what to do in the first 5 seconds if you fall into a tree well or deep powder pocket, why thrashing causes immediate snow compaction and suffocation, how partners must tunnel in horizontally from the downhill side rather than stepping on top of the hole, and how to prevent tree well traps on powder days.

Yenza lokhu manje¶

1. Uma uwa ngasemthonjeni wesihlahla: dedela izigxobo zakho bese ubamba isiqu sesihlahla noma amagatsha ngokushesha. Ungalokothi ubeke izandla zakho ngaphakathi kwebhande le-ski pole esihlakaleni lapho ugibele eduze kwezihlahla. Njengoba uwa, yelula ngezandla zombili ukuze ugone isiqu sesihlahla sokhuni esiqinile noma amagatsha angaphezulu aqinile ukuze umise ikhanda nesifuba sakho ukuthi singawi singene esikhaleni esingezansi.
2. If you land upside down in snow: DO NOT thrash, kick, or wiggle your legs. In loose, unconsolidated powder snow, struggling acts exactly like a mechanical cement vibrator: every kick knocks hundreds of kilograms of snow off the boughs above and packs it tighter around your chest and face, sinking you deeper. Freeze your legs immediately.
3. Create a breathing air pocket in front of your mouth and nose first. Before the snow settles, cross one forearm or cup your hands in front of your face to push a small 10- to 15-centimeter (4- to 6-inch) hollow space around your mouth and nose, and tuck your chin or pull your neck gaiter/collar up to keep loose powder from falling into your airway when you inhale.
4. Hlala uzolile, phefumula kancane, bese ushaya impempe yakho (uma iseduze nomlomo wakho). I-panic hyperventilation idla ngokushesha iphakethe lakho elincane le-oxygen futhi incibilikisa iqhwa ebusweni bakho ngomoya ofudumele, ophinde ube yiqhwa elicwebezelayo elingangeni moya ("imaski yeqhwa"). Uma ukwazi ukufinyelela isiqu somuthi ngesandla esisodwa, bambelela kuso ukuze ungasheleli ujule, bese ulinda umlingani wakho.
5. Uma unguzakwethu ngaphandle: UNGALOKOTHI unyathele unqenqema lwembobo noma udonse isisulu uqonde phezulu ngamabhuzu/ukushushuluza. Ukunyathela onqenqemeni olungaphezulu lwesihlahla kugoqa ithani leqhwa liqonde ngqo ekhanda lomngane wakho, bese ugibela phezulu kuma-ski ezishicilele noma ibhodi leqhwa kuyisa ikhanda laso lijule emgodini.
6. Call Ski Patrol or emergency services immediately and dig horizontally from the side or downhill toward their head. Shout for nearby riders to help, call the resort Ski Patrol emergency number (or call your local emergency number: 911 in the United States and Canada, 112 across the European Union, 999 in the United Kingdom; see our izinombolo eziphuthumayo directory), locate the victim's head beneath the boots, and tunnel inward from the side/downhill to clear an airway around their face before unclipping their bindings.

Immediate survival and partner rescue decision flow¶

Whether you are the rider falling into a tree well or the partner who just saw your friend vanish under the boughs, follow this sequence immediately.

flowchart TD
    A["Rider Falls Near Conifer Tree or Deep Powder Pocket"] --> B{"Which Role Are You In Right Now?"}
    B -->|"I Am the Rider Falling Into the Tree Well"| C["Drop Ski Poles Immediately and Grab Tree Trunk or Heavy Branches"]
    C --> D["Stop All Leg Thrashing and Kicking to Prevent Snow Funnel Collapse"]
    D --> E["Cup Hands or Forearm Over Mouth & Nose to Carve a Breathing Pocket"]
    E --> F["Hold Onto Trunk if Reachable, Breathe Slowly, and Wait for Partner Excavation"]
    B -->|"I Am the Partner Outside Who Saw Rider Disappear"| G["Keep Strict Visual Fix on Exact Tree (Mark With Upright Skis or Pole Outside Rim)"]
    G --> H["Call Resort Ski Patrol Emergency Number / 911 / 112 and Yell for Nearby Riders"]
    H --> I["DO NOT Step on Top Lip of Hole and DO NOT Pull Up on Victim's Skis or Snowboard"]
    I --> J["Probe Gently With Hand Along Trunk to Locate Victim's Head and Chest Depth"]
    J --> K["Tunnel Inward Horizontally From the Downhill Side Directly to Victim's Face"]
    K --> L["Clear Snow From Mouth and Nose First, Then Release Bindings and Extract"]

How a tree well forms and why conifers look safe from above¶

Many skiers and snowboarders assume that if there is 2 meters (6.5 feet) of fresh snow on the open ski run, the snow stays flat right up to the trunk of every pine, fir, spruce, or hemlock tree. In reality, low-hanging evergreen branches act like a giant umbrella:

1. The branch umbrella: As meters of snow fall over the winter, the wide, downward-sloping lower branches of fir, spruce, hemlock, and cedar trees catch the falling snow and prevent it from reaching the ground around the base of the trunk.
2. The hidden 2-to-3-meter (6-to-10-foot) void: Directly beneath the bottom branches sits a deep, conical pit of air, tangled dead branches, and loose, uncompacted feathers of dry snow extending all the way down to the bare forest dirt or rocks, even when the surrounding snowpack is 3 meters (10 feet) deep.
3. The visual illusion: From 5 meters (16 feet) uphill, the snow-covered outer tips of the tree branches blend smoothly into the smooth powder slope. A rider carving a turn too close to the outer branch skirt ("skirting the tree") breaks through the thin crust of branch tips and drops straight into the hidden vertical shaft headfirst.

Step-by-step survival protocol if YOU fall into a tree well¶

Uma uhluleka ukulawula noma ubamba unqenqema futhi uzizwa uphonsa ikhanda kuqala ngaphansi kwamagatsha esihlahla somgulukudu, izenzo zakho kumasekhondi okuqala angu-3 kuya kwangu-5* ngaphambi kokuthi iqhwa lizinze zinqume ukusinda kwakho.

Step 1: Fight to stay upright or arrest your slide on the trunk¶

• Never wear ski pole wrist straps in the trees: If your hands are looped inside pole straps when you fall into a tree well, the poles catch on branches and pin your arms backward over your head so you cannot reach your face to clear snow. When skiing glades or off-piste powder, always hold your pole grips without putting your hands through the wrist loops.
• Hug the trunk or thick inner branches: As you crash through the outer boughs, lunge with both arms for the solid wooden tree trunk or thick inner limbs and wrap your arms or legs around them like a climbing koala. Even if your skis drop below you, keeping your head and shoulders hooked over a branch above the pit saves your life.
• Try to roll onto your back or side (tuck and roll): If you are pitching over your handlebars in deep open powder away from a tree, tuck your chin and roll onto your side or back so your face points toward the sky rather than burying face-down.

Step 2: Stop all kicking and create your breathing space¶

If you are already inverted inside the tree well and snow is cascading around you:

1. Freeze your legs immediately: Every human instinct screams at you to kick your legs and try to swim upward. Resist that urge completely. Because your skis or snowboard are 150 to 185 centimeters (5 to 6 feet) long and locked inside stiff branches above you, kicking your legs cannot move you upward, it only shakes the tree canopy and packs hundreds of kilograms of loose snow tightly down around your head and ribcage.
2. Lock an arm across your face ("The Boxer Guard"): Bring one or both hands immediately to your face. Sweep a hollow cavity around your mouth and nose, and hold your forearm or cupped hands a few centimeters in front of your mouth so settling snow stops against your arm instead of pressing flat against your lips and nostrils.
3. Spit out any snow in your mouth before inhaling: If snow entered your mouth during the tumble, spit it out or sweep it out with a gloved finger before taking a deep gasp of air so you do not aspirate powder into your windpipe.
4. Expand your chest as the snow settles: Take a deep breath and hold your elbows slightly outward for the first 10 seconds while the loose snow settles around your torso; this leaves a important 2-centimeter (1-inch) expansion gap around your ribcage so you can still breathe in and out once the snow stops moving.

Step 3: Can you ever self-extricate if you are completely alone?¶

In landmark field tests conducted by tree-well researcher Paul Baugher (Northwest Avalanche Center), 90 percent of test subjects placed into real tree wells could not get out on their own. For the 10 percent who managed to self-rescue, or if you broke the #1 rule of powder skiing and rode into the trees alone, here is the only technique that ever works:

• Only move with slow, deliberate, millimeter movements: Never jerk or thrash.
• Keep one hand anchored on the solid tree trunk or a thick root/branch: Use the tree trunk itself as your only solid ladder rung.
• Do NOT try to push against the loose snow wall: Instead of trying to climb up the snow, see if you can slowly reach up along your own leg to pop your ski binding heel piece or unbuckle your snowboard ankle straps, only if your upper body is already wedged securely against the tree trunk so releasing your feet will not cause your body to slide 1 meter (3 feet) deeper down the bottomless shaft.
• Check if you can wriggle further DOWN or SIDEWAYS along the bare trunk: On steep slopes, the downhill side of the tree well often has a thinner wall of branches and snow than the uphill side. Sometimes a trapped rider can pull themselves against the bare bark of the trunk and push sideways out through the lower downhill skirt of branches rather than going up.

Partner rescue: how to dig someone out of a tree well without killing them¶

Over 80 percent of tree well victims die simply because their partners kept skiing all the way down to the bottom of the chairlift, waited 15 minutes at the lift line wondering "Where is Dave?", and then rode the chairlift back up to start looking, by which time 30 minutes had elapsed and the victim had already suffocated.

When you ride within visual and voice contact of your partner and see them tumble into a tree well (or see a single ski tip, snowboard base, or glove sticking out beneath a conifer tree), you have under 15 minutes to get air to their face.

CRITICAL PARTNER EXCAVATION RULES FOR A TREE WELL:
1. NEVER step onto the top rim of the snow cone around the tree (collapses snow onto the victim's face).
2. NEVER grab the victim's boots, skis, or snowboard and yank upward (drives their head deeper and breaks legs/spine).
3. ALWAYS approach from the DOWNHILL or SIDE of the tree and tunnel INWARD HORIZONTALLY straight to the victim's head.

Step-by-step partner excavation protocol¶

1. Mark the tree and call for backup immediately:
   • Plant your own skis or poles upright in the open snow 3 meters (10 feet) uphill of the tree so approaching Ski Patrol or other riders can spot the exact tree instantly (in a dense forest of 500 identical fir trees, taking your eyes off the tree for ten seconds can make you lose the spot).
   • Yell loudly "HELP. SKIER IN A TREE WELL HERE." to flag down passing riders on the run.
   • Have a second person (or use your speakerphone while moving) call the resort's Ski Patrol Emergency Direct Line (program it into your phone before riding; it is printed on every paper trail map and lift tower) or dial 911 / 112 / 999 with the exact trail name and lift tower number.
2. Stabilize the victim's feet so they do not slide deeper:
   • If you can see the victim's boots, skis, or snowboard tangled in the upper branches, do not pull them up, and do not unclip their bindings yet if those snagged skis are the only thing holding their body from dropping another meter down into the bottom of the pit.
   • Instead, if a second rescuer is present, have them gently hold or lash the victim's boot/leg steady in place so the victim cannot slip deeper while you tunnel to their head.
3. Assemble your avalanche shovel and tunnel in from the DOWNHILL SIDE:
   • Look at the angle of the victim's legs to estimate exactly where their head and chest are resting against the tree trunk (usually 1 to 1.5 meters / 3 to 5 feet below their boots).
   • Step around to the downhill side (or lower flank) of the tree well, staying completely off the upper snow lip.
   • Use a collapsible aluminum avalanche shovel (or your hands/snowboard if you have no shovel) to cut a horizontal doorway straight inward through the lower branches and snow wall at the level of the victim's head, shoveling the snow downhill away from the tree so it cannot slide back in.
4. Clear the airway around the mouth and nose FIRST:
   • The moment your gloved hand touches the victim's helmet, jacket, or shoulder, stop using the metal shovel blade near their head so you do not strike their face.
   • Sweep the snow away from their mouth, nose, and chest with your hands, pull down any snow-packed neck gaiter or scarf, and scoop any snow plug out of their mouth.
   • Check immediately if they are conscious and breathing:
     • If they are conscious and breathing: Keep their airway wide open, reassure them, widen the horizontal trench around their torso so their chest can expand freely, and only then release their ski bindings or snowboard straps above so you can slide them gently out through your side tunnel.
     • If they are unresponsive and not breathing (or only gasping): Extricate them onto a flat stamped platform immediately while protecting their neck, open the airway, give 5 initial rescue breaths (because tree well cardiac arrest is caused by hypoxia / asphyxiation, rescue breaths paired with chest compressions are critical if you are trained; if you cannot give rescue breaths, start continuous hands-only CPR at 100 to 120 compressions per minute immediately) and continue until Ski Patrol arrives with oxygen and an AED.

How to prevent tree well and deep snow immersion tragedies¶

Every single tree well fatality is preventable by following five non-negotiable powder-day rules endorsed by the National Ski Areas Association (deepsnowsafety.org) and MountainSafety.info:

• 1. Keep your partner in direct visual sight at all times (Not just "meet at the bottom of the lift"): Riding "with friends" does zero good if you split up at the top of the run and meet at the chairlift ten minutes later. In the trees or on deep powder days, ride in short leapfrog pitches keeping your partner within direct line of sight (or constant voice call-and-response every 15 seconds) until both of you exit the trees.
• 2. Take your hands OUT of ski pole wrist straps before entering any glade or off-piste run: Pole straps turn your ski poles into anchors that pin your arms above your head in a tree well and dislocate thumbs/shoulders on branches. Let your poles go the instant you lose balance.
• 3. Wear a loud pea-less survival whistle clipped right next to your chin: Tape or clip a 120-decibel pea-less plastic whistle (such as a Fox 40) onto your jacket zipper pull or backpack sternum strap just 10 centimeters (4 inches) from your mouth so you can reach it with your teeth even if both arms are pinned against your chest.
• 4. Carry an avalanche transceiver (beacon), collapsible metal shovel, and probe, even IN-BOUNDS on deep powder days: Many skiers leave their avalanche beacon and shovel in the car when skiing inside resort boundaries. On any day with 30+ centimeters (12+ inches) of fresh snow or when skiing resort tree glades, wear an active 3-antenna digital avalanche transceiver (457 kHz) in SEND mode and carry a pack with a metal shovel. A partner with a transceiver and shovel can pinpoint and excavate a completely buried rider under a tree in 3 minutes instead of spending 20 minutes guessing which tree they fell under.
• 5. Give conifer trees a wide berth, never cut turns under the branch drip-line: Stay out in the open white lanes between trees rather than hugging the trunks, control your speed so you can stop before hitting obstacles, and watch out for small 1-meter (3-foot) "baby" evergreen tops sticking out of the snow, that tiny green treetop is actually the crown of a 6-meter (20-foot) tall tree with a giant hidden well underneath the snow surface. For related winter mountain emergencies, read our skiing, snowboarding, and slope accidents, iziqhwa, futhi ihlane hypothermia kanye nokubanda abaqondisi.

Imibuzo evame ukubuzwa¶

Imithombo ihloliwe¶

• I-Northwest Avalanche Centre (NWAC, United States) kanye no-Paul Baugher (Umqondisi we-Crystal Mountain Ski Patrol): I-Tree Well and Deep Snow Safety (deepsnowsafety.org), I-Empirical Tree Well Immersion Survival Research kanye ne-Partner Excavation Protocols.
• I-National Ski Areas Association (NSAA, United States) kanye ne-Canada West Ski Areas Association (CWSAA, Canada): Imihlahlandlela Yokuvimbela Ukuphepha Kweqhwa Okujulile Nokucwiliswa Kweqhwa (SIS).
• I-International Commission for Alpine Rescue (ICAR / CISA-IKAR, International / Switzerland) kanye ne-Wilderness Medical Society (WMS, United States): Imihlahlandlela Yokuzilolonga Yomtholampilo Yokuvimbela Nokuphathwa Kwezisulu Ze-Avalanche Nezingezona Zeqhwa.
• I-Avalanche Canada kanye ne-Canadian Ski Patrol (Canada): Imithombo Yesihlahla, Ukucwiliswa Kwempuphu Ejulile, kanye Namazinga Okuvuselela Ukungcwatshwa kwe-Asphyxial.
• I-European Resuscitation Council (ERC, European Union) kanye ne-American Heart Association (AHA, United States): Izimo Ezikhethekile Zokuvuselela, I-Accidental Hypothermia kanye ne-Asphyxial Arrest Ventilation Protocols.

Iziqondiso ezihlobene¶

• Izingozi ze-skiing, i-snowboarding, ne-slope
• Ama-avalanche
• I-Wilderness hypothermia kanye nokubanda
• I-CPR yezandla kuphela