Brittany Dogs -
As you noted, snow is heavy. And when rain falls, the water can't run off because the snow soaks it up like a sponge, and the whole mass is REALLY REALLY heavy. I hope your TM is closed, so it can withstand all that weight. When it is open, it cannot support all that weight! Check your owners manual, where it says that 1 foot of dry snow is OK, but two feet of snow, or snow with water in it (rain) must be removed, or you risk damage (and it ain't minor!)
Bill