Long fire and reflector wall for warmth

A fire warms you mainly through radiation – the same kind of heat you feel when the sun warms your face even though the air is cold. This heat travels in straight lines. Anything not facing the fire gets hardly any. A long fire as long as your body therefore radiates evenly onto the whole side of your body.

A reflector wall behind the fire first of all blocks the wind, which would otherwise carry heat away and swirl smoke and sparks around. It also warms up and radiates some of that heat back. That helps a little, but not as much as is often claimed. The bigger benefit is usually the wind protection.

The long fire is most effective in front of an open shelter, such as a sloping tarp roof whose open side faces the fire. Then the heat reaches you directly while the roof keeps off the rain.

Wood, wood and more wood. A fire for a whole night consumes enormous amounts – much more than most people estimate. Gather before dark, and then gather the same again. Looking for wood in the dark is hard work and dangerous.

Choose an open spot with no overhanging branches, across the wind, so that the smoke does not blow into your shelter. Keep enough distance between the fire and your sleeping place: you want to feel the warmth, but no spark should reach you. Better a smaller, steady fire than a big one that throws sparks.

Build the reflector wall from logs stacked between driven-in stakes, or from dry stones. Do not use wet stones or stones from streams or lakes: they can crack when heated and throw fragments.

A fire you sleep next to is always risky. Sparks can set sleeping bags, tarps and clothing alight; synthetic fibres melt and stick to the skin. So never leave the fire unattended. In a group, someone always keeps watch and adds wood while the others sleep; alone, a long fire overnight can hardly be run safely.

Never bring fire or embers into a tent, vehicle, snow shelter or enclosed room. Carbon monoxide can build up there – an invisible, odourless gas that can be fatal. The shelter in front of a long fire must be open towards the fire.

Check the local rules and wildfire danger before every fire; during a fire ban or drought, a long fire is out of the question. Keep extinguishing water ready and put the fire out completely in the morning. For burns, cool immediately with cool running water and call the local emergency number (112 in the EU) for serious burns.

The long fire is a technique for genuine cold emergencies: an unplanned bivouac in the cold with an open shelter, plenty of deadwood nearby and a group that can take turns keeping watch. In North American and Scandinavian wilderness traditions it is a classic element; bushcraft authors such as Mors Kochanski have described it in connection with open shelters.

In many situations it is not the right choice: alone without anyone to take turns, in areas with little deadwood, under trees, in rain where it can hardly be kept going, or anywhere fire is not permitted. Clothing, insulation from the ground and shelter from wind remain the foundation. The fire is a supplement, not a replacement.