Nothing in the backcountry gives off heat like a fire. That’s why our recent ancestors built fireplaces in their log cabins, and why more remote forebears burned fires in whatever structure they called home. Since it’s not wise to have a fire in a primitive hut made of sticks and dry vegetation (or a cave, for that matter), it’s good to know other ways to heat your living and sleeping area. By digging a hot rock heating pit in the dirt floor of a shelter, you can enjoy the heat of a fire – with far less danger. Here’s how.
Start by digging a small pit in the floor of your shelter, a little bigger than the bowling ball sized rock that you will be using to transfer heat. Dig the hole to match the rock’s size and shape, and find a flat rock to cover the pit. Make sure that you get your two rocks from a dry location (water-logged rocks tend to explode when heated).
Ensure that everything fits together well before you heat up the stone, since a 1200-degree rock isn’t a fun thing to juggle. You could even recess the flat rock around the edge of the pit, so that it is level with the floor (not a trip hazard). When it’s time to use your set-up, heat up your pit stone in a fire for about an hour (but don’t heat the lid stone), carry the stone to the pit (a shovel works well), and drop it in.
Seal the pit with your flat stone lid, and bask in the radiant heat that will last for several hours. This trick works best in very dry soil and with a red hot rock. Just clear all flammables out of the way as you move the near-molten stone toward the waiting pit!
Have you ever used hot rocks as a heat source for survival?