Hi, Doug,

Thank you.

It's a good idea to keep a few tricks up one's sleeve for those "oh, shoot" moments when you realize that the weather forecast is off by 20 degrees (colder) than expected. It happens, particularly on multi-day trips.

Basically, anything that adds warmth to one's canister will make it run better. Peeing on the canister, putting the canister in one's groin area, chemical hand warmers, wrapping a copper wire around the canister and running the ends of the wire into the flame, putting the canister into some warm water, a tight windscreen, all of these can be used. Some more dangerous, some completely safe. The thing to remember if you're ever in a pinch and need to warm a canister is that the canister should never be hot to the touch. Pay constant enough attention to the canister, and pretty much any work around can be used.

All that being said, if you know that the temp is going to be much below 32F/0C, I think my approach would be to get a stove appropriate for the weather. I mean at a certain point it's time to stop screwing around and get something specifically for the situation at hand. For cold weather, I'd bring one of the following:
a) A gas stove where I can invert the canister, turning the stove into a liquid feed gas stove.
b) A specialized gas stove designed to run in liquid feed mode.
c) A liquid fueled stove (Coleman type fuel or kerosene).

If one weren't as concerned about weight or bulk, 100% propane stoves will work in very cold weather. Propane will continue to vaporize down to -44F/-42C. Of course the process of vaporization causes the canister to get colder, so a more realistic expectation for vaporization would be higher. Disclaimer: I'm speaking here about the physics of gas at 1 atmosphere of pressure. I have never been in temperatures even approaching -44F/-42C. There are many other factors affecting gas stoves beyond just fuel vaporization temperatures. If you're heading out into that kind of weather, you'd do well to spend a lot of time talking to people with field experience. Anecdotally, I know that the US Army Northern Warfare school uses liquid fueled stoves, and every article I've read about Polar expeditions talks about liquid fueled stoves.

HJ