Dakota fire hole

Hot air rises. In the fire pit, the hot gases rise straight up and leave the hole. For that to happen, fresh air has to follow – and the easiest route for it is the tunnel from the air hole. This creates a constant flow of air that arrives right at the base of the fire. It is the same chimney effect as in a stove.

Because the air comes from below and the fire burns in a narrow shaft, combustion is intense. The wood burns hot and thoroughly, relatively little smoke forms, and the flame is barely visible from the side. The surrounding earth shields the fire from wind.

The ground decides everything. Only firm mineral soil is suitable – that is, sand, gravel, clay or earth without many roots and without a dark, spongy, organic layer. Dig a test hole first. If you see roots or peaty, dark soil, find another spot or do without the Dakota hole.

Lift the turf in pieces and put it aside so you can replace it later. The fire pit should be about a forearm deep and slightly narrower at the top than at the bottom. The air hole goes on the windward side, a short distance away. If the holes are too close together, the tunnel easily collapses.

Feed the wood in fairly upright so it slides down well. Rest the pot on two green sticks or stones across the opening so that there is still room for air and flames underneath.

The biggest danger is invisible: embers that lodge in roots or peaty soil can smoulder underground for days and eventually start a fire somewhere else entirely. So dig only in pure mineral soil and never in bog, humus or among the roots of trees.

Put the fire out completely before you refill the hole: pour in plenty of water, stir, add water again until nothing hisses any more. Then carefully check with your hand whether any warmth can still be felt. Only when everything is cold do you put the soil back and replace the turf. Buried embers do not reliably go out – they can keep glowing underground.

Before digging, check whether digging and fire are allowed at all; in protected areas and at times of increased wildfire danger both are usually prohibited. An open hole is also a trip hazard – mark it while it is open. Cool burns immediately with cool running water; for serious burns, call the local emergency number (112 in the EU).

The Dakota hole is useful in strong wind, when an open fire would be hard to control, and for wood-saving cooking. It is described in military survival manuals, including as a way to make a low-profile fire.

It is hardly suitable for warming a group, because the heat rises and radiates only a little to the side. On stony, frozen, peaty or root-laced ground it is not possible or too dangerous. And it costs time and effort – half an hour of digging or more, depending on the ground.

Leave No Trace principles generally advise against digging new fire pits where existing ones can be used. A small stove is the simpler and gentler alternative in many situations.