Last nite I made a fire in my Solo 60. After about 15 minutes of burning I went outside to see a continous flow of sparks and embers coming out of my chimney and landing on my roof. Winds were 35mph from the north. I have not seen this before. Visual inspection showed a clean chimney and I think my bypass damper is closeing tight. If my roof was not covered in snow I think I would have been nervous. Any thoughts?