Survival · FHS pillar

Four shelters, four reasons to pick each one.

The shelter you build is the shelter the environment gifts you — wood, snow, debris, and a tarp are four different gifts. Each card below lists the build steps, the conditions it suits best, and the cautions that come with it.

ChecklistFirst-aidShelterForaging
Shelter
Lean-to

A-frame of poles against a ridge or crossbar.

Best when

Dry wood country, breezy ridge or forest edge, fire can sit in front of the open side.

Build steps
  1. Drive two stout uprights 1–2 m apart and ridge a horizontal crossbar 1.5–2 m off the ground.
  2. Lean shorter poles against the crossbar at a 30–45° angle, close enough to shed rain.
  3. Lay branches, bark sheets, or boughs shingle-style from the bottom up, so water sheds down the slope.
  4. Pile leaves, pine needles, or dry grass against the back wall for insulation.
  5. Build a fire 1–2 m in front of the open side so heat reflects inward.
Cautions
  • A lean-to only protects your back. Wind and driving rain from any other direction will soak you.
  • Heat retention is poor — without a deep bed of duff under you, the ground steals more heat than the fire gives.
  • Never sleep directly between the fire and the lean-to — sparks onto the boughs are a real risk.
Shelter
Snow cave

Tunneled into a wind-packed drift or snow wall.

Best when

Deep, consolidated snow (a forearm pushed all the way in fails to reach your elbow) and no avalanche slope above.

Build steps
  1. Find a drift on the lee side of a ridge or tree — wind-packed snow holds shape better than loose powder.
  2. Probe for voids and weak layers; dig an entrance trench 1–1.5 m long, slightly downhill, to trap cold air below the sleeping platform.
  3. Carve a tunnel wide enough to crawl through, then excavate a dome UP and OUT so the ceiling stays arched — flat ceilings sag and collapse.
  4. Punch a ventilation hole 10–15 cm wide through the ceiling near the top; a candle by the entrance will tell you whether air is moving.
  5. Mark the entrance with a tall pole and a flag so searchers or you-in-a-storm can find it.
Cautions
  • A wet or frozen sleeping bag is now your insulating problem; ventilation matters even more when you are damp from melting snow.
  • CO2 builds up in a closed snow cave — the ventilation hole is not optional.
  • Avoid digging under tree wells, cornices, or on an avalanche slope — the cave can collapse on you while you sleep.
Shelter
Debris hut

Tripod ridgeline buried under leaves, bracken, and boughs.

Best when

Abundant dry leaf litter, bracken, or boughs; no heavy rain expected; mild cold.

Build steps
  1. Drive two sturdy forks (or a tripod) and ridge a long pole between them at knee-to-hip height — long enough to lie down on.
  2. Lay closer-spaced ribs from the ridge down to the ground at a steep enough angle to shed water.
  3. Pile leaves, bracken, ferns, or evergreen boughs 60–90 cm deep on top — fluff matters more than weight.
  4. Add a thick bed of the same dry litter INSIDE for ground insulation; this is where you lose or keep most heat.
  5. Block the entrance with a rucksack, pack of loose debris, or a small door-wall — keep the wind out, not the lay-of-the-land.
Cautions
  • A debris hut only works when leaf litter is genuinely abundant — pine needles alone compress and lose loft fast.
  • You will get damp from below if you skip the bed — and that damp kills faster than the outside cold.
  • A debris hut is not a rain shelter in heavy weather; the leaves hold surface water.
Shelter
Tarp shelter

A-line, lean-to, or plow-point pitched over a ridgeline.

Best when

Carrying a tarp + cord; rain expected; no snow load; a tie-off point (trees, rocks, stakes) within reach.

Build steps
  1. Pick two anchor points for a ridgeline (or a tree + stake if you only have one) and tie a taut line 1–1.5 m off the ground.
  2. Drape the tarp over the line, pull the two long edges taut to opposing anchors, and stake the corners.
  3. Pick an A-line or plow-point pitch — A-line for sun, plow for driving rain; never a flat horizontal pitch (it pools water).
  4. Stake the foot of the tarp higher than the head if rain is coming from behind, so splash does not enter.
  5. Set your sleeping pad and bag inside the footprint, but stay shallow — touching the tarp walls transfers cold.
Cautions
  • A poorly-pitched tarp pools water and collapses on you in a storm — re-tension when you can hear it slap or sag.
  • Hypothermia sets in faster under a tarp in cold rain than under a debris hut, because there is no radiant warmth around you.
  • Cord + tarp + stakes are only as good as their tie-offs; carry a knot you can tie half-asleep in the wind.