After about 20 years with no broken windows at my cabin, last winter a lump of ice in late May shattered one of my casements. The furnace came on and it cost me about $500 in propane because I didn't go up there for a while to check on things. Looking for a solution, I came across these heavy duty closet channels at Home Depot, and they seem to work very well for framing a Plexiglas storm window to shield the glass from falling snow. I cut the Plexiglas into 3 pieces to make it easy to store during the summer.

I used 3/16 inch Plexiglas, and the total cost of materials was about $200 for a 5'x5' window.

Below are some photos of the installation.

The web address for the channels can be found at: