Eunice wrote:
I have a postcard of the lava tube during winter and it is spectacular with the ice hanging from the ceiling so we are going to see it for ourselves.
I wondered why you were coming all the way to Lassen when you could go camping in the mountain snow closest to your home. Now, I understand!
However, I would think you could see the ice hanging from the lava tube anytime during the winter or spring. I think Lassen stays snowed in until late April or early May. I've been there at the end of April, with snow piled 10 feet high. My guess is that the longer you wait into the winter, the longer the icicles will be when you see them. Maybe you could check with a ranger and they could tell you when the best time would be (if you haven't already). I think part of Highway 89 gets closed down for the winter, too. I wouldn't want you to make that trek just to be disappointed in the scenery, especially since that's what you're going for.
PS. Remember, Lassen has underground, sealed ice-filled lava tubes that never totally melt and keep the nights in the 30's even in August. I would think that the open lava tube would stay ice cold for a number of months.