This may not be relevant to your situation but I'm wondering if you're certain the water you see is from the snow. I say that because I had a similar problem with a 2006 25' Safari. In my case, the problem had to do with the air conditioner condensation drip line that goes from the top of the trailer, along an inside wall to a drain point in the left wheel well. The water dripped down the line OK but an Airstream worker did a lousy job where the very end of the line was supposed to exit the wheel well. In my case, too large a hole was drilled in the wheel well. The water dripped down the condensation line to its end then somehow came back into the coach through the overly large hole. Under warranty, I think caulk was used around the exist hole for that line to stop water dripping out of the end of the hose line from coming back inside.