THE PLT OF THE AIR TAXI CARGO FLT WAS OPERG AT NIGHT IN MARGINAL VFR CONDS WHEN THE ACFT STRUCK RISING TERRAIN. THE ACFT WAS FND THE NEXT DAY AT APRX 1000 AST, SOME 15 MI OFF THE INTENDED ROUTE. THE PLT WAS UNCONSCIOUS & SUFFERING FM HYPOTHERMIA & OTHER INJURIES. HE WAS TAKEN TO A HOSPITAL, BUT DIED LATER THAT DAY. AN INVESTIGATION REVEALED THE ACFT STRUCK THE SOUTH SIDE OF BISMARK MTN AT APRX 2100' MSL WHILE IN LVL FLT. ANOTHER PLT, WHO WAS FLYING IN THE AREA ABOUT 2-1/2 HRS AFTER THE ACDNT, RPRTD THAT CLASSIC WHITE-OUT CONDS EXISTED WITH MOD SNOW FALL & ICE CRYSTALS RDCG FWD VIS TO LESS THAN 1/2 MI. THE PLT (OF N9979M) HAD BEEN RECENTLY HIRED BY BERING AIR & HAD ONLY ABOUT 23 HRS OF KNOWN FLT TIME IN THE GENERAL AREA. AT THE TIME OF EMPLOYMENT, HE INDCD HE HAD APRX 1536 HRS OF FLT TIME; HOWEVER, ONLY 446 HRS OF FLT TIME WAS VERIFIED BY HIS LOGBOOK & OTHER SOURCES. MIN FLT TIME TO ACT AS A PIC IN THE AIR TAXI OPN WAS 500 HRS.