Yes the ephemeral art are very much a performance as about the finished piece. I have also made a few fire sculptures in my day. I like the way you create something only to have it's destruction the performance.
I like you friends sculpture. Here in Ireland last winter we had some really heavy snow but I didn't get a chance to make anything because I was hard at work in my studio doing some wood work. Hopefully next year I'll get a chance.
Thanks for you comment and sorry for the late reply.
Following you now also.