I live near Canada (northern NY) so this is something I have to plan for --

My plan includes two milspec poncho liners, small backpack of warm clothing, water, datrex survival bars, various PSK signaling devices, tea candles, and a trangia alcohol stove to heat warm drinks. I should probably add a couple of sleeping bags, but haven't yet.

My understanding is that an alcohol stove does not produce carbon monoxide (which would include the survival heater referenced above). However, I think you would still need ventilation.

Interested in responses: does burning alcohol produce CO?

Above all, I would avoid making things really complicated and relying solely on some mechanical/electrical device that would probably fail just when you need it.

Tim

Those are remarkable. I recently opened a couple up whose sell-by date was 2008. They were plenty warm and lasted for hours.

Makes it harder for rescuers to find your car or other motorists or snowplows to keep from running into it.

REI is selling "HELP" blaze orange vinyl signs half-off. Good thing to put over the snow-covered car cave.

Yes, and I always carry at least couple of flashers with plenty of extra batts to keep them going. And the vinyl signal marker is a must as even a brightly covered bandanna will be white from snow and ice sticking to the cotton cloth.

I carry a couple of the survival candles tucked in under where the backseats are permanently folded down. Can't remember what brand they are. They would generate some heat for sure. Just make sure to always crack a window and make sure to determine which way the wind is blowing so you don't have snow or wind blowing into the vehicle.

Any combustion can create CO given the right (or wrong) circumstances -- a low oxygen environment. Hydrogen is the only one that shouldn't, at least in theory; though IIRC very hot objects in contact with air are known to give off small amounts of CO directly.

Many CO detectors won't work properly below a certain temperature. Read the specs before relying on one.

Ventilation is always needed, not only to keep the oxygen level up but to vent out some of the moisture. Moisture kills insulation, and the amount you breathe out is surprising.

I've always carried a stash of candles in the car with appropriate containers. If they are tea lights, I carry a bit of extra wick or twine to make them burn a bit hotter on demand. I'm leery of an open pot of flammable liquid in such tight quarters: one jostle as I'm dozing and I can turn my emergency shelter into a smoke-filled mess. Yikes.

I carry sleeping bags, and coleman cadalidic heater. I also have way too many stoves!

In a blizzard, the snow will often cover the vehicle for you. It's not a bad idea to add more. I think you would need to have a foot at least to gain substantial insulation value, and three feet would be better. Also, don't discount the gains of building up a windbreak and loosely wrapping the vehicle in whatever tarp material you may have.

Signalling is important though. A high-speed plow can total a vehicle. I always carry a few of those orange flags from building supply stores that are used for long loads (hey, they're blaze orange, multipurpose, and free). I also have one or more bicycle flasher lights, the red LED jobs, in each car. That preserves the battery, and you can mount the flashers on a stick or a tripod on the roof. There's nothing worse than coming back to retrieve a vehicle and finding the battery is dead and destroyed due to freezing.

I guess it is time for an "off the beaten path" story. Throw another log on the fire....

I was driving solo in the White Mountains of Arizona, on my way to a rendezvous with two friends to embark on a fairly long ski tour (four days). As I got into the mountains it began to snow and night fell. I was creeping along in reduced visibility when progress stopped as I lurched into an impassible mound of snow. It was about 10 at night.

No problem. I was equipped for sleeping out in this weather anyway (my friends were bringing a tent, so I did not have that, but I was packing everything else, including stove, fuel, and food and water), so I simply got out my sleeping bag and slept.

In the morning, as rosy-fingered dawn was creeping through the trees, I awoke, had breakfast, and listened. Sure enough, I could hear a snowplow approaching. I was quite surprised (think the expression on the face of Wil E, Coyote) when I saw the snowplow roar by on the highway, which was on an embankment about fifteen feet above me.

In the storm, I had followed an abandoned road segment down into a deep drift. Had I gone a little further, I would have found that the bridge across the small stream was missing.

I was almost in town, so I packed up, put on my skis, and started touring a little bit early.

Had I actually been on the active roadway, some sort of signal would have been a good idea, although the car was never covered.

I am glad we are having these heated discussions.....

I was in the Air Force in North Dakota for 4 years. We were trained to carry a survival bag for each person in the car. Enough blankets and clothes to survive overnight in way below zero temperatures. The recommendations back then (early 70s) were to watch your fuel and run the engine with the heater on if possible. If it was snowing or there was blowing snow, have someone get out and check the exhaust to make sure it wasn't blocked. Crack a window on the leeward side of the car for ventilation.

We were also told to carry candles to light in the car (with a cracked window) if we couldn't run the engine. I never had to use any of this, so I don't know how well candles worked as a source of heat.

The issue I have with being stranded in the winter is that you won't know how long it will be till you're rescued, so providing heat in the cabin of your vehicle is not a good solution - you'll run out of gas, propane, candles if you aren't rescued promptly. My idea is that I should have sufficient gear in the car to keep us all warm enough to survive our coldest temps without further heating. I'd say body heat is the best, most renewable, and longest lasting source.

We also carried food with us.

I have to say the gear the AF issued to its members was excellent. I was out in very high winds at way below zero at nights and while it wasn't pleasant no one was cold in our winter outfits, not even toes and fingers. Now I live in the San Francisco Bay Area and it hasn't been below freezing since we moved here in '94.