WHILE ATTEMPTING TO LAND THE PLT ENCOUNTERED GUSTY, QUARTERING, CROSSWIND CONDITIONS. THE PLT LOST CONTROL OF THE AIRCRAFT AND IT NOSED OVER. THE WINDS, 20 NM NW WERE REPORTED OUT OF 300 DEGREES AT 13 KTS GUSTING TO 22. THE PLT ESTIMATED THE WINDS AT THE ACCIDENT SITE TO BE FROM 340 DEGREES AT 15 KTS GUSTING TO 30 WITH MODERATE TURBULENCE.