We used to make similar flares by buying handheld boating flares and cutting off the bottom half (where it's designed to be hollow, so you can hold it with your hand). It makes a half-size flare that's waterproof and easy to pack.

I keep them in all my snowmobiles, since they're easy to use (even with poor hand dexterity) and provide instant heat/flame. You do have to be very careful with them though, as they burn very hot and drip molten hot chemicals while burning.