DCA84AA012

During landing the crew acquired visual reference with the ground & apch lights about 200 ft AGL, followed by visual sighting of the rwy. Since the ATIS reported blowing snow, the crew expected to see, & was not surprised to see, snow blowing across the rwy about 2,000 ft beyond the threshold. At about 2,200 ft down the rwy the acft entered a cloud of snow, & the right wing struck a large snow sweeping vehicle which was traveling in the same direction & to the right of the rwy centerline. The acft's right wing separated & it swerved off the rwy. Neither the approach controller nor the local controller advised the flt of snow removal operations, nor did the local controller communicate with the sweeper after he took the hand-off of the flt from approach control. He also stated he did not know where the sweeper was when he cleared the flt to land.