Front end vibrates when going over 50-55mph on 2007 Saturn Ion

I drove my 2007 Saturn Ion on sunday with no problems than we had a blizzard here in the Boston area I shoveled out my car from the snow yesterday and did not use it until this morning on the highway and to my surprise my car stared to vibrate/shake at 50-55mph. What happened or could of happened? I wont be able to get it to a mechanic until this friday...Help!!

Asked by for the 2007 Saturn Ion
could be as simple as ice inside the wheels that cause a gross wheel balance change.
take it to a car wash and use the hot water to get rid of all the snow and ice in the wheels.

Thanks! I'll give it a try