THE INSTRUMENT RATED PVT PLT WAS COMPLETING A PERSONAL IFR FLIGHT FROM TELLURIDE, COLORADO, TO COLORADO SPRINGS, COLORADO, WITH THREE PAX. THE DESTINATION WX WENT BELOW IFR MINIMUMS PRIOR TO THE FLIGHT'S ARRIVAL AND THE AIRCRAFT DIVERTED TO PUEBLO, COLORADO, FOR AN INSTRUMENT LANDING. WX WAS 300 OBSCURED, VISIBILITY 1 MILE, TEMPERATURE AND DEWPOINT 30 DEGREES, WIND 090 AT 5 KNOTS, RESTRICTIONS TO VISIBILITY WERE FOG AND SNOW. DURING THE APPROACH TO RNWY 8L, WINDSCREEN ICING OCCURRED AND ICE COULD BE SEEN ON THE AIRCRAFT SURFACES. AT FLARE FOR TOUCHDOWN, THE AIRCRAFT WAS SLOWED TO 70 KNOTS AT 5 FEET OF ALTITUDE AND STALLED. A HARD LANDING RESULTED, AND THE AIRCRAFT TAXIED TO PARKING. NO DAMAGE WAS VISIBLE AND THIS INCIDENT WAS UNREPORTED UNTIL A MECHANIC DISCOVERED FIREWALL DAMAGE DURING A HARD LANDING INSPECTION LATER.