OFF ARPT LNDG.

Narrative

AFTER RECEIVING A WX BRIEFING AT DBQ FSS; I WAS TOLD THAT AN AREA OF RAIN SHOWERS AND POSSIBLE TSTMS MIGHT EXIST 35-40 MI S AND SE OF DBQ IN ISOLATED AREAS. THE VISIBILITY INFLT WAS APPROX 7-10 MI WITH A CLOUD BASE OF ABOUT 3000 FT ASL. NO PRECIPITATION AT ALL AND SMOOTH AIR. WITH THIS WX ABOUT; THE ISOLATED TSTM AND RAIN SHOWERS IN THE MIND; IT APPEARED TO ME THAT IF I WOULD FLY STRAIGHT E OF DBQ THAT I COULD PROBABLY FLY AROUND THIS WX. AS I WAS ABOUT 15 MI NW OF THE PERU; IL; ARPT; LIGHT RAIN BEGAN TO FALL FOR ABOUT 25-30 SECONDS. THE VISIBILITY WAS ABOUT 6 MI NOW. THEN THE RAIN SHOWERS STOPPED AND CLR ICE IMMEDIATELY BEGAN FORMING ON THE AIRPLANE. I TRIED TO GO STRAIGHT TO VYS AND LAND THERE. THIS ARPT WAS ABOUT 15 MI TO MY SE. THE ICE FORMED SO FAST THAT I COULD NOT HOLD ALT EVEN WITH FULL THROTTLE. ABOUT 1 MI N OF THE ARPT; I DID NOT KNOW FOR SURE THAT I COULD MAKE THE RWY WITH THE ALT THAT I HAD LEFT. BTWN ME AND THE RWY WAS A FEW BUILDINGS; TRUCK STOP; MOTELS AND PWR LINES. I MADE THE DECISION TO LAND IN A CORNFIELD. NO INJURIES OF ANY KIND OCCURRED TO ME OR MY SON AND HIS FRIEND. NO PROPERTY DAMAGE TO ANYTHING ON THE GND. THIS ICING CONDITION WAS NOT FORECAST AND; WHEN ENCOUNTERED; CAME ON FAST. IT WAS ABOUT XA00 PM IN DAYLIGHT CONDITIONS. THE ENG RAN GOOD THE ENTIRE TIME. I DON'T KNOW WHAT TO RECOMMEND FOR PREVENTIVE ACTIONS FOR THIS PARTICULAR AND PECULIAR WX PHENOMENON AS RAIN SHOWERS AND TSTM ACTIVITIES WERE POSSIBLE IN THE FORECAST AND NO ICING CONDITIONS WERE FORECAST IN THIS AREA. MY DISCUSSION WITH THE FAR REPRESENTATIVE ON THE TELEPHONE TOLD ME THEY WERE CONSIDERING THIS AS AN INCIDENT AND NOT AN ACCIDENT AND THAT THEY WOULD NOT PROBABLY COME OUT TO THE AIRPLANE AND LNDG SITE. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR FLEW INTO FREEZING RAIN THAT WAS BOTH AERODYNAMIC AND STRUCTURAL (WT) IN NATURE. HE WAS FLYING A C-172 WITH NO ICE PROTECTION. HE LANDED IN A SOFT CORN FIELD AND BROKE OFF THE NOSE GEAR WITH NO INJURY. THE FAA HAS CLASSIFIED THIS AS AN INCIDENT. THE RPTR REMAINED CLR OF CLOUDS AT ALL TIMES DURING THIS INCIDENT.