A friend and his wife were in s snowstorm on the way home from s ski trip and rather than drive the icy, snowy road late at night, they pulled off into a small country store parking lot off the highway and had sleeping bags and munchies in the car. He had taken his candle lantern just in case and lit it and hung it in the middle of the roll bar, old Toyota Forerunner, he also cracked a window down on the lee side of the wind. It helped provide warmth, keeps the humidity down and gives off a nice light.
I always take one snow camping and hang it from the peak of my tent, works well and before I got older and lost some of my vision, I could read by the light. Main thing it does in a tent is keep the frost down inside the roof of the tent and of course provides some heat.
Try looking for a small candle lantern, REI carries them. Cheers!