Pilot of light twin reports loss of control on landing roll due to icy runway and snow drifts. Nose gear collapses when the aircraft is redirected into snow drifts by the snow drift's drag on the left main gear.

Narrative

I was executing the RNAV 2 approach into ZZZ. ATIS information was reporting light winds from 330 degrees; reported the runway had been plowed and sanded full length and width; and reported light snow over thin patchy ice with braking action of 40-50-40 degrees. I executed a normal touchdown; at which time the aircraft began to track left. Smooth and timely addition of full right rudder managed to momentarily correct the nose position; however; the aircraft continued to drift towards the left side of the runway. At no time were the brakes applied; both heels were on the floor. The left main landing gear struck the snow bank on the left side of the runway; which caused a yawing moment to the left. Almost immediately; the nose gear struck the snow bank and collapsed as the aircraft came to rest at approximately 2;000 ft down the runway. After the aircraft came to a complete stop; I simultaneously turned off all electrical switches and pulled the mixture; prop and throttle controls to idle-cutoff while checking with my passengers to insure no one was injured. I then ordered an immediate evacuation of the aircraft. Subsequent inspection of the touchdown zone revealed that the grooves in the runway were in fact packed with ice to the point that walking in the vicinity of the touchdown area was treacherous. A follow-on test of the braking action revealed that ATIS Information was optimistic; as the braking action was less than reported; and decreased steadily towards the edge of the runway.