Shelter

Dig a snow cave

A snow shelter may reduce wind exposure, but cannot guarantee warmth, roof strength or survival. Snow conditions, insulation and construction skills matter. This research-based lesson covers precautions, not a certified design or a substitute for supervised winter training.

Shelter 90 min practice Advanced Use deep, cohesive snow on gentle terrain away from avalanche slopes, their runout zones, cornices, streams, and terrain traps. Lee slopes and drifts can hold wind-loaded, unstable snow, so choose one only when you can establish that the site and all slopes above it are outside avalanche terrain.

All skills

Topic summary

Key takeaways

You can explain why the route and site must be outside avalanche exposure and overhead hazards.
Your plan includes appropriate sleeping insulation, dry clothing, an outside partner and a backup.
You can identify an unobstructed exit and ventilation openings; those observations do not certify safe air or roof strength.
You know to stop if snow cracks, sags, sheds material or openings cannot be maintained.
Avoid: Assuming a convenient drift is outside avalanche exposure.
Avoid: Treating a fixed roof dimension, elapsed time or visual inspection as engineering approval.

Intended uses

Shelter skill (Advanced, ~90 min practice)
Requires: Snow shovel, Avalanche probe or long measuring stick, Long stick for making and clearing ventilation holes, Ski or tall branch for marking the entrance

Climate suitability

Use deep, cohesive snow on gentle terrain away from avalanche slopes, their runout zones, cornices, streams, and terrain traps. Lee slopes and drifts can hold wind-loaded, unstable snow, so choose one only when you can establish that the site and all slopes above it are outside avalanche terrain.

Ray Mears — Building a Snow Cave Watch on YouTube

Safety: Do not excavate an enclosed shelter alone. Keep a capable partner outside with a shovel and a backup shelter. Avoid avalanche exposure, cornices and snowplow areas. Keep exits and ventilation clear; do not use stoves, candles, heaters or other combustion inside. A clear vent does not certify safe air.

Required tools

Snow shovel
Avalanche probe or long measuring stick
Long stick for making and clearing ventilation holes
Ski or tall branch for marking the entrance

Required materials

Deep, cohesive snow
Sleeping pads
Packs or spare dry gear for supplemental floor insulation
Already fallen evergreen boughs, only where available and collection is permitted

Step-by-step

Check the route, site and terrain above it against local avalanche guidance; do not dig into a cornice or an exposed drift.
Why: NPS warns against traveling or camping in avalanche zones; assess slopes above the site, not just the ground beneath it.
Learn snow assessment and excavation in supervised winter training with an outside partner, a shovel and a viable backup shelter.
Why: The Mountaineers documents burial during a training excavation; an outside partner is a conservative precaution, not a guarantee of rescue.
Do not rely on a fixed roof thickness or dome shape as structural approval; leave if snow cracks, sags or sheds material.
Why: Snow bonding varies; generic dimensions and the absence of cracks cannot establish structural strength.
Keep the exit and ventilation openings clear as snow drifts or ices; ventilation does not make a stove, candle or heater safe inside.
Why: NPS warns about oxygen use and carbon monoxide from cooking in shelters. CDC identifies CO as odorless and colorless; a small vent is not permission to burn fuel inside.
Use a full-length insulated sleeping pad, protect dry clothing, mark the cavity and follow local dismantling rules when leaving.
Why: NPS lists a full-length insulated sleeping pad among winter essentials; a snow shelter does not replace appropriate sleeping equipment.

Common mistakes

Assuming a convenient drift is outside avalanche exposure.
Treating a fixed roof dimension, elapsed time or visual inspection as engineering approval.
Digging until clothing is wet or fatigue undermines judgment.
Using a flame inside or assuming one vent guarantees ventilation.
Depending on a snow shelter instead of suitable clothing, sleeping insulation and a backup.

Troubleshooting

If the roof cracks, sags or sheds snow, leave and reassess from outside; do not repair it from underneath.
If airflow or the exit cannot be maintained, use the backup shelter or leave for a safer alternative.
If anyone becomes confused, unusually drowsy, weak or dizzy, leave for fresh air and seek urgent help; do not diagnose the cause inside.

Field practice drill

Attend supervised winter-skills training with qualified instruction, dry clothing, appropriate sleeping insulation and an alternative shelter. Practise hazard recognition and safe access without treating a practice duration, measured thickness or apparent roof condition as permission to sleep inside.

Indicators of success

You can explain why the route and site must be outside avalanche exposure and overhead hazards.
Your plan includes appropriate sleeping insulation, dry clothing, an outside partner and a backup.
You can identify an unobstructed exit and ventilation openings; those observations do not certify safe air or roof strength.
You know to stop if snow cracks, sags, sheds material or openings cannot be maintained.

Related outdoor skills

Sources

Educational reference only. Wilderness conditions change fast — practice in low-stakes settings, take a certified wilderness first-aid course, and confirm regional regulations before you rely on any of these skills in the field.