Writing letters really works. I think your letter is great. Adding a little shame to them if they have been promoting alternative transportation is a good suggestion, too.

Whether you are a bike lane hater or lover, having a bunch of snow in the bike lane means less room for everybody on the road. God knows with these crazy, distracted drivers these days you need all the room to escape them you can get. At least snow is pretty soft, right? (How would I know?)