You may have packed for a day hike and still end up out after dark. A wrong turn, sudden storm or injury can make it unsafe to keep going. Here is how to prepare for an emergency overnight stop, decide when to stop and protect yourself while you wait for help.
What is a bivouac?
A bivouac is a temporary outdoor overnight stop using simple shelter or gear. It can be planned as part of a route or forced by an emergency.
A planned bivouac allows you to pack for the night and check where overnight stays are permitted. An emergency bivouac is a stop you did not expect to make because conditions or an injury have made it unsafe to continue.
On a day hike, you still need enough shelter, clothing and equipment to wait out a delay in the conditions you might encounter. Know how to use what you carry before setting out.
A waterproof shell reduces exposure to wind and rain. You also need something to retain body heat and insulate you from the ground if you have to stay still for hours.
Three pieces of equipment for an unplanned stop
On day hikes as well as overnight routes, carry equipment that works for the cold, wind and rain you could face.
- Emergency shelter. A lightweight group shelter, tarp or bivy bag can reduce exposure. Learn how to set it up, keep air circulating and follow the manufacturer’s instructions.
- Emergency blanket or bivy. A reflective cover can reduce heat loss. Pair it with dry layers and something to insulate you from the ground. Keep the face clear.
- Headlamp and spare power. A hands-free light helps you set up shelter after dark and signal for help. Check batteries before departure and carry compatible spares or a power supply.
Carry extra food and drinking water for delays. Choose food you can eat without cooking and check whether water sources along the route are available and safe.
Choose the equipment for the route, season and group. Weight varies widely, especially if you need insulation for more than one person. Pack what is adequate for the conditions you may have to wait in.
What to do if you have to stay out
Decide to stop while you still have light, energy and a clear head if continuing would put you at risk. If you need rescue, contact responders as early as you can.
It is tempting to press on in the hope of getting down. Assess the remaining daylight early, along with terrain, injury, weather and the distance to a known safe place. Darkness on unfamiliar ground can make slips and wrong turns more likely. Use these priorities when stopping is safer.
- Choose a site. Look for shelter from the wind and avoid exposed ridges, unstable rock, steep slopes, streambeds and places that could flood. Move only as far as needed to get out of danger.
- Limit heat loss. Put on dry layers, cover your head and neck, and place a pad or pack between you and the ground. Use your emergency shelter or blanket while keeping the face clear.
- Call for help. In Japan, call 110 for police or 119 for fire and medical emergencies. Give coordinates or landmarks, your condition and the gear you have. Use satellite SOS if available when there is no signal. Conserve battery and stay reachable as the dispatcher advises. Stay where you can be found if the location is safe.
- Eat and drink if you can do so safely. Use your reserves in manageable amounts if fully alert and able to swallow. Give nothing by mouth to someone who is confused, very drowsy or unable to swallow. Report any deterioration to rescuers.
Rules for fire and camping vary by area, including within national parks. Avoid lighting fires in unauthorized places or when conditions could spread a fire. Use the shelter and insulation you brought to stay warm.
Insulate yourself from the ground
Contact with cold ground can drain heat quickly. Put an insulating mat, spare clothing or your pack underneath you. Put dry layers over and around you and keep out of wind and rain. A thin reflective sheet works best alongside insulation.
What to remember
Emergency gear is useful even when you expect to be home by evening. A wrong turn, injury or sudden change in weather can put anyone in a position where waiting is safer.
Carry shelter, insulation and a headlamp on day hikes. Choose a place and call for help before darkness, cold or exhaustion make it harder. Keep your group together where possible and follow the directions from rescuers.
Practice setting up your shelter and using your emergency equipment before a hike. Local courses and qualified mountain guides can help you practice in conditions similar to those on your route.