Site Selection & Microclimates

Overview

Where you stop often matters more than what you carry. Good sites keep you dry, block wind, reduce radiant heat loss or gain, and avoid overhead and ground hazards. In towns, “safe rooms” protect from glass and debris while preserving breathable air.

Skill Level: Basic

Drainage

Keep water moving past you, not through you.

Avoid low spots, gullies, dry streambeds (arroyos), and depressions that become ponds in rain.
Prefer slight rises or benches with a gentle slope (1–3°) so water sheds away.
In storms, camp 60–70 m (200–230 ft) above rivers/creeks and away from floodplains.
In snow, pack the surface flat to prevent body heat from melting you into a cold trough.

💡 Tip: After a short rain, look for where needles and leaves accumulate—nature’s “flow map.”

Deadfall

Scan up before you commit.

Widowmakers: Dead limbs/tops hung in trees; avoid camping within 1.5× the height of suspect trees.
Leaners: Wind‑loaded or root‑compromised trees, especially after saturated soils or burn scars.
Snow/ice load: Under thawing branches or eaves; thaw cycles drop ice unexpectedly.

⚠️ Caution: Wind shifts at night. Sites safe at calm dusk can become dangerous by midnight.

Wind Breaks

Block wind without moving into a venturi or rotor.

Use terrain: Leeward side of knolls, behind rock outcrops, or in sparse trees (not directly under dead limbs).
Set back from ridge crests by ~10–30 m on the lee side; avoid saddles where wind accelerates.
In sand/snow, build low walls; leave a gap for controlled airflow to reduce condensation.

📝 Note: Cold air pools in valley bottoms and hollows. Even a 10–30 m rise can be markedly warmer on still nights.

Diurnal wind patterns

Day: Sun warms slopes; upslope/valley breezes can build through afternoon and spill over saddles.
Night: Cold, dense air drains downslope (katabatic). Expect downslope trickles into gullies and basins; avoid camping in drainages even if dry.

⚠️ Caution: Lightning risk grows on exposed ridges and near tall isolated trees. Follow 30/30 guidance (see Risk Assessment) and move off high ground when storms approach.

📝 Note: 30/30 Rule — If the time between a lightning flash and the thunder is under 30 seconds, you are close enough to be struck. Get to a safe building or a fully enclosed metal vehicle immediately and wait at least 30 minutes after the last thunder before resuming exposed activities (NOAA Lightning Safety: https://www.weather.gov/safety/lightning-outdoors).

Radiant Hazards

Manage heat gain/loss from nearby surfaces.

Wilderness: Big rock faces radiate heat after sunny days (can be helpful) but also radiate cold to clear night skies (frost pockets). Don’t bed directly against heat sinks.
Urban: South‑facing masonry/glass (N. hemisphere) can superheat rooms by day; metal and concrete radiate heat at night. Choose interior walls and insulated floors if possible.

Urban Safe Rooms

Pick spaces that protect from glass, debris, and exterior hazards.

Tornado/high wind: Small interior rooms on lowest floor, away from windows; sturdy furniture to shelter under.
Earthquake: After shaking stops, avoid exterior walls and glass curtain facades; be cautious of stairwells until inspected.
Air quality/hazmat: Choose a room with few vents; seal gaps with tape/towels; run only safe air filtration.
Fire/smoke: Prioritize egress paths; keep doors closed to control smoke; stay low.

⚖️ Legal: Know building policies for access and alarms; do not block exits.

💡 Tip: For smoke days, a simple DIY “clean room” air filter (often called a Corsi–Rosenthal box) made from a box fan and MERV‑13 filters can noticeably improve indoor air. Use UL‑listed fans, orient filters correctly, and never leave running unattended in unsafe locations.

Standoff Distances (Rules of Thumb)

Watercourses: 60–70 m (200–230 ft) setback to reduce flood risk and contamination.
Cliffs/cornices: Stay back at least body length + pack from edges; more in snow/corniced ridges.
Trees: Avoid within 1.5× tree height of dead/dying trees in wind.
Avalanche slopes/runouts: Avoid obvious avalanche paths, loaded lee slopes, and runout zones. Most slab avalanches occur on slopes ~30–45°. Check your local avalanche forecast before travel (e.g., https://avalanche.org) and avoid avalanche terrain entirely without training and proper gear.

☑️ Checklist — Site Quick Scan

Ground drains away from sleeping area
Overhead clear of dead limbs/ice/glass
Wind break present without venturi
Away from flood/slide/rockfall/avalanche paths
Thermal: not in cold sink; has ground insulation
Urban: interior room, sealable, two egress options if possible

Examples

Shoulder‑season storm: Bench 20 m above creek, lee of low ridge, no overhead hazards; pitch low A‑frame, dig shallow trench to shed runoff.
Hot urban blackout: Interior hallway room with door; block light leaks, open window only on the shaded side at night, create cross‑breeze with a fan if power exists.

📝 Note: Near water, insect pressure can be intense. In bug seasons, camp 50–100 m off water with slight breeze exposure and use head nets/repellent as needed to balance drainage with comfort.

Common Mistakes

Camping in low spots, dry creek beds, or floodplains—good views, bad drainage.
Ignoring overhead hazards (dead limbs, ice, glass façades); wind shifts at night.
Perching on windward ridges or saddles that accelerate wind; step to the lee shoulder instead.
Sleeping in cold sinks when a short climb gains warmer air.
Sitting too close to water for convenience; spray, condensation, and flood risk soak gear.
Urban: Choosing glass‑heavy rooms for “light” instead of interior safe rooms.

Key Takeaways

Dry, wind‑sheltered, hazard‑free ground beats most gear shortcomings.
Think in three layers: drainage (ground), wind (air), radiation (surfaces/sky).
In towns, pick interior rooms away from glass; in wild, pick benches away from lows/highs.

Scenarios

🧭 Scenario (Temperate storm): Two benches—one near creek, one lee of a low ridge.
🔍 Decisions: Drainage vs wind vs overhead hazards.
✅ Outcome: You pick the lee bench, stake low, trench lightly where allowed, and stay dry.
🧠 Lessons: Drainage + wind break beats “pretty view”
🏋️ Drill: Walk a park after rain and map water flow.

🧭 Scenario (Urban smoke): AQI spikes; ash falling.
🔍 Decisions: SIP room vs leave; sealing; ventilation.
✅ Outcome: You choose an interior room, seal, run HEPA, and monitor alerts.
🧠 Lessons: Interior, sealable rooms win smoke days
🏋️ Drill: Stage tape/towels in your chosen room.