ON THE DAY PRIOR TO THE ACCIDENT, THE PLT NOTED THAT THE FUEL GAGE INDICATED 30 TO 35 GAL REMAINING. HE ADDED 40 GAL & MADE A FLT OF ABOUT 15 MIN. ON THE NEXT DAY, HE NOTED THAT THE GAGE INDICATED ABOUT 40 GAL OF FUEL REMAINING. THE REPORTED FUEL CONSUMPTION WAS APRX 1 GAL/MIN. HE TOOK OFF WITHOUT REFUELING; HOWEVER, ABOUT 18 MIN LATER, THE LOW FUEL WARNING LIGHT CAME ON, & SHORTLY THEREAFTER, THE ENG FLAMED OUT FROM FUEL EXHAUSTION. THE PLT MADE AN AUTOROTATION, BUT THE HELICOPTER WAS DAMAGED DURING THE LANDING ON SNOW COVERED, MOUNTAINOUS TERRAIN. AN EXAM OF THE FLOAT TYPE FUEL QUANTITY GAGE REVEALED THAT IT WAS CORRODED. DUE TO THE CORROSION, THE FLOAT WOULD NOT FREELY MOVE UP & DOWN IN ITS HOUSING. THE LOW FUEL WARNING LIGHT WAS ELECTRICALLY CONNECTED TO THE FUEL QUANTITY TRANSMITTER & SHOULD HAVE ILLUMINATED WHEN THE FUEL LEVEL DROPPED TO 60 LITRES (15.85 U.S. GAL). THE CRASH SITE WAS LOCATED ON WOODED TERRAIN AT AN ELEVATION OF 6480 FT.