Incident Description
The pilot reported a normal approach and touchdown. During the initial roll-out, the aircraft unexpectedly veered to the right, departing the runway surface and striking a snowbank approximately 3 to 4 feet in height.
Runway Conditions
An investigation revealed that snow had been falling for more than 12 hours prior to the incident. A path 80 feet wide had been plowed down the center of the runway; however, approximately 3 inches of snow remained in the plowed area. Although no ice was explicitly reported at the time, braking action was characterized as nil.
Pilot's Account
The pilot stated that a previous ice storm had deposited between 1/4 and 1/2 inch of ice on the runway before the snow began to fall. The presence of ice had been indicated earlier in the day when a Boeing 737 slid off a taxiway. The pilot said that had he known about the ice, he would not have landed.