Most of the time when we have a high-speed shake the problem is tire balance not alignment. It may also be caused by a bad tire or an out of round tire, your service center can inspect the tires and let you know just what needs to be done to correct the problem. If you are having this kind of issue it should be checked sooner than later, if you have a bad tire it may let you down any time or any where.
We had a little visitor to the shop today. She was just so adorable!