How to make a survival stove, and how to keep warm in a stranded car

Getting stuck in a car in a snowstorm is a real winter risk across the northern states, and every car kit for cold country needs a plan for heat. The engine is the obvious answer, but fuel runs down, and a running engine with a snow-blocked tailpipe can fill the cabin with carbon monoxide.

A tip that circulated widely around 2009 was to build a cheap alcohol stove and burn it inside the car as a heater, with a window cracked. Do not do it: an open flame burning in a closed vehicle risks carbon monoxide poisoning, oxygen depletion and an upholstery fire, and safety agencies do not recommend it. The stove itself is still worth building. Use it outside the vehicle to melt snow and heat water, and use the methods further down to keep warm inside.

What you will need

• A small metal can, a little taller and narrower than a roll of toilet paper. An empty 1-quart paint can from a hardware store is ideal because its lid seals. A clean food can will do.
• A larger metal can that the small one sits inside with room to spare, such as an empty 1-gallon paint can, a coffee can or a small metal bucket.
• A metal lid or plate that can cover part of the small can.
• A roll of unscented toilet paper.
• Isopropyl (rubbing) alcohol, 70 to 91 percent. Several bottles, since the stove burns it quickly.
• Matches, a lighter or a ferro rod.

How to put it together

1. Pull the cardboard tube out of the toilet roll, leaving only the paper.
2. Squash and roll the paper into the small can until it fills the whole volume. If the roll is too fat, unwind outer sheets until it fits snugly.
3. Pour in alcohol until the paper is soaked through. With a quart paint can, you can fill it ahead of time and hammer the lid on for storage, which keeps the fuel from evaporating and saves space. Check the seal regularly and store it in a vented spot away from heat.
4. Stand the small can inside the large one. The outer can steadies it and keeps the heat off whatever it sits on.
5. Set it on bare ground, rock or packed snow, well away from the car, dry grass, fabric and anything overhead.
6. Light it with a long match or sparks from a ferro rod, keeping your face and hands back. Alcohol vapor catches all at once with a soft whoosh.

Controlling the burn

Left fully open, the small can throws a tall flame and burns through its fuel fast. To slow it, slide a metal lid part of the way across the opening. With a quart paint can, punch a quarter-sized hole in its own lid and set that on top; the flame then burns steadily from the hole for much longer.

A second approach is to soak the paper with only a few ounces of alcohol and add more as it burns down. Never pour alcohol onto a can that is still lit or hot. Put the flame out by covering the can completely with a metal lid, let it cool, then refuel.

Rubbing alcohol burns with a sooty yellow flame and leaves black residue on pots. It is a camp fuel for an emergency, not a replacement for a proper stove.

Staying warm inside a stranded car

The National Weather Service’s winter safety guidance gives the safe routine:

• Stay with the vehicle. Walking off into blowing snow is how people get lost.
• Run the engine about 10 minutes each hour for heat, and switch on the dome light so rescuers can see you.
• Before each run, clear snow away from the exhaust pipe, and open a downwind window slightly while the engine is on.
• Raise the hood or tie a bright cloth to the antenna once the snow stops, to show you need help.

Between engine runs, keep the heat in your body rather than the air. Pack wool blankets or a sleeping bag, a hat, spare dry socks and gloves, and huddle together if there is more than one person. Hot water from the alcohol stove, heated outside and poured into a sealed bottle rated for boiling water, makes a good heater inside a sleeping bag; wrap it in a sock so it cannot burn skin.

A battery carbon monoxide alarm in the car kit is cheap insurance for the engine runs. Headache, dizziness, nausea and drowsiness are the early signs of carbon monoxide poisoning; if anyone has them, open the doors, get fresh air and switch off the engine.