I have a Rheem Classic 90 plus furnace that has been working great. Last night we received a lot of snow (here in Northeast) and this morning the furnace was not heating. I could hear some start-up sounds, however when it would be time for the blower to start, the furnace would just shut off. I did two things, 1) replaced the air filter, which was quite dirty. 2) removed some snow that was around the exhaust/intake pipes outside the house. The pipes weren't completed covered and blocked in snow, but there was snow around them. The furnace started working again and I'm wondering if anyone has any ideas as to what happened?