THE PLT REPORTED THAT HE HAD STAYED IN THE LOCAL AREA & HAD BEEN PRACTICING SLOW HOVER OVER THE GRASS BESIDE THE RWY. THERE WAS A PAVED RAMP THAT HE HAD TO CROSS, EACH TIME HE WENT FROM ONE END OF THE RWY TO THE OTHER. HE SAID WHEN HE CAME TO THIS AREA, HE WOULD CLIMB TO ABOUT 35 TO 50 FT, BEFORE CROSSING. AFTER CROSSING THE RAMP, HE WOULD LET DOWN ON THE OTHER SIDE. ACCORDING TO THE PLT, THE WIND CHANGED AS HE WAS CROSSING THE RAMP WHICH RESULTED IN A TAIL WIND. AFTER HE STARTED BACK DOWN, THE HELICOPTER WOULD NOT STOP DESCENDING UNTIL IT HIT THE GROUND. IT BOUNCED APRX 10 TO 12 FT IN THE AIR. DURING THE BOUNCE, THE PLT FELT AN UNUSUAL VIBRATION & HAD VERY LITTLE CONTROL. THEREFORE, HE SHUT-OFF THE MASTER SWITCH & LET IT FALL. APRX 2 FT OF THE TAIL BOOM WAS CUT OFF, THE SKIDS WERE BENT UP & THE BELLY & MAIN ROTORS WERE DAMAGED. REPORTEDLY THE IMPACT OCCURRED WHILE THE HELICOPTER WAS SETTLING WITH POWER APPLIED.