Sleeping in the cold is terrible if you are unprepared. When you spend a night in the cold you struggle to stay warm by tossing, turning and trying to best cover up yourself in all the places where the cold might try to sneak in. I have had bad outings, hanging in a hammock where the night just got cooler than I thought and sleep eluded me almost completely.
Sure, you can be prepared with the right clothing but skills like heating rocks for warmth have great value. We are going to teach you how to heat rocks and use them to keep you warm for the night.
Why Heat Rocks for Warmth?
If you can just build a raging fire that will keep you warm all through the night, then what is the worry? Why do you need to heat rocks for warmth?
Well, anyone who has set out to build a nice big fire that will heat them through an entire night’s sleep has realized that in about 2-3 hours that fire is reduced to little more than smoldering ash. You can get up and revive that fire, but most people just huddle up tighter in their sleeping bag or under blankets and deal with it.
When you know which kinds of rocks, what size and how to heat them properly you can actually warm the ground underneath of your camp and that warmth goes a long way.
What Size Rocks
The size of the rocks that you choose will make all the difference in this. If your rocks are too big they will not fit inside the hole you are digging under your camp. You cannot sleep directly on hot rocks and if they are too close to the surface they will be too hot!
If the rocks are too small then they will not capture and radiate enough heat over time. Your sleeping area might be warm on cold nights but only for a little while. The right size hot rocks can become an overnight heat source.
The rocks should be about the size of a full-sized football. This sized rock can hold a lot of heat and will keep your body warm.
Rocks that Go Boom
Knowing what kinds of rocks to use is also important. You might think that you can head down to the creek and find some football-sized rocks that are sitting along the shore. Well, that might blow up in your face, literally!
Rocks that sit in or around the water’s edge are often porous rocks. Not porous in the sense that you can see through them but that they hold water inside their small crevices. When you apply heat to these kinds of rocks crazy things can happen. Heating rocks that are filled will small amounts of water can crack from the pressure of the steam being created inside of them.
Sometimes they can explode!
Rocks around water sources are not the ones you are looking for. Instead, you should head uphill and look for rocks that are dry and dense. The best rocks for holding heat are soapstone so getting to know how to identify it will help.
How Long to Heat Them
Once you find about 10-15 good rocks to heat up you are going to need a fire. The rocks should be “cooked” for 1-2 hours in the fire. You are trying to heat those rocks down to the core. This will allow them to radiate the most heat for the longest period of time.
Place the rocks directly in the fire. You can also turn them in hot coals on the outskirts of the fire, too. I find that when heating rocks, it’s a good idea to leave the squarest ones you find on the outskirts of the fire and use them to cook on.
Once they are hot they are perfect to sit pans on or even boil water on.
How to Warm Your Shelter or Bedroll With Heated Rocks
- Begin by finding the location where you will be sleeping. If you have already pitched your tent then you are going to have to take it down or move it for the time being.
- Using a shovel or trowel you are going to dig out a 12×12 area that is about 6 inches deep. Try to stay true to the depth. If your rocks are too deep then they are not going to warm you. If your rocks are too shallow then the heat will be unbearable
- Using large forked sticks or the spade of your trowel, fill the hole with all of your football-sized rocks. Cover them with dirt. Smooth out your dirt.
- Build your shelter over this patch of heated ground and set your sleeping area on this location.
- At this point, you are ready for bed. Manage your layers properly so you don’t sweat through your clothes and wake up wet.
Heating Rocks for Warmth
If your goal is to keep a fire going and stay warm by the flame all night, well, that is not as easy as it might sound. Not to mention there are some inherent safety risks to falling asleep by a campfire. You do not want to wake up with your favorite tent melting onto your face and sleeping bag because your campfire went rogue.
By using the rocks as conductors of heat they have a massive heat capacity that can warm you all night. If you can find the right rocks for the job and you can build your camp around these warmed buried rocks, you are in for a good night’s sleep.
Coupled with the right kind of sleeping bag, and layered warm clothes, you will be as snug as you can be just by using this method for heating rocks. In my experience, you will be taking off hats and layers of clothes throughout the night, even when it is cold out!