I'm a little shocked that no one has mentioned solar chargers here. Often the snowstorms themselves arent longer than the life of an e-reader, its the cleanup and long lasting power outages afterwards that are the problem.
Mind you, I speak being from a hurrican region and not a snow region, so correct me if I'm wrong. But
this little fella is indespensible for me. i usually leave it on the dash of my car and never have a dead device.