The pilot of the Piper PA-46-350P reported checking the weather information for the arrival airport during the execution of an instrument approach. He stated that the weather report indicated the winds to be light, and that the runway had been plowed and sanded, and was covered with light snow and patchy ice. Just after touchdown the airplane began to drift to the left; the pilot then countered with the gradual application of right rudder. The airplane momentarily straightened out, but as the ground speed decreased the airplane continued the left drift. The airplane then departed the runway and collided with a snow bank causing substantial damage to the firewall.