Here on OFFGRIDweb, we've already described several methods of constructing a focused, intense fire—namely, the rocket stove and the Swedish torch. These concentrated jets of flame are ideal for cooking food, boiling water, and other small tasks. However, what do you do if your objective is to create a large area of warmth to blanket your campsite? For that purpose, you'll need a different type of fire altogether.
The traditional cone-shaped teepee campfire is a good all-around choice, but it still doesn't radiate as much heat as you may need in frigid conditions. Fortunately, there's a technique called the long fire that fits the bill perfectly.
The long fire technique utilizes two long logs stacked on two short spacers, like stumps, rocks, or other logs. The raised platform allows air to enter at the base of the fire, sustaining the flames. Between your two long logs, you can add kindling and tinder to get the fire going—the burning will eventually ignite the logs themselves.
This video from AlfieAesthetics shows how it's done: