THE ACFT MADE A HARD LANDING AND NOSED OVER DURING A FORCED LANDING AFTER ENGINE FAILURE ON THE BASE LEG. THE FLT WAS ONTHE BASE LEG WITH POWER AT IDLE AND CARBURETOR HEAT ON WHEN THE ENGINE LOST POWER. THE PILOT WAS UNABLE TO RESTART THE ENGINE. THE PILOT STATED THAT HE WAS SO TROUBLED BY GUSTS ON THE FINAL APPROACH HE ABANDONED RESTART ATTEMPTS. ACCORDINGTO HIM A GUST THAT STOPPED LEFT HIM AT 10 FT AGL DURING FLARE. HE ALSO SAID THE MUDDY FIELD THAT WAS FRESHLY PLOWED CAUSED THE NOSE OVER. PICTURES, A WITNESS AND THE INSURANCE REPRESENTATIVE STATE THE FIELD WAS NOT MUDDY. GROUND VEHICLEDROVE TO THE SCENE WITHOUT DIFFICULTY. GROUND SCARS IN THIS UNPLOWED FIELD SHOW EVIDENCE OF A NOSE WHEEL ONLY FIRST GROUND CONTACT. THE FLAPS WERE AT 10 DEGREES. THE ENGINE WAS STARTED AFTER THE ACCIDENT AND OPERATED NORMALLY. THE RELATIVE HUMIDITY ON THE DAY OF THE ACCIDENT WAS 90 PERCENT WITH TEMPERATURE AT 61 DEGREES F AND DEW POINT AT 58 DEGREESF. ACCORDING TO ICING PROBABILITY CURVES THIS IS IN THE SERIOUS ICING RANGE FOR GLIDE AND CRUISE POWER.