VEHICLE SPUN OUT ON SNOWY ROAD AND SLID OFF THE ROAD AT A ~120 ANGLE TO DIRECTION OF TRAVEL (LEFT ROAD FACING RIGHT AND BACKWARDS) AT AROUND 45MPH. STRUCK A SIGNPOST IN THE DRIVER'S DOOR, THEN ROLLED OVER ONCE DOWN A ~30 EMBANKMENT TO LAND BACK ON WHEELS. SIDE AIR BAGS DID NOT DEPLOY. DRIVER SUFFERED FRACTURED CLAVICLE.