DURING A VFR FINAL APPROACH TO A GLACIER THE PILOT ENCOUNTERED A LOW FOG BANK. THE PILOT STATED, 'ON SHORT FINAL WITH FULL FLAPS AND A LOADED AIRCRAFT LANDING AT THIS LOCATION, A GO AROUND IS IMPOSSIBLE, I WAS COMMITTED TO LAND. UPON DESCENDING FURTHER I FOUND MYSELF IN A GROUND FOG AND LOST GROUND CONTACT....THE LANDING WAS HARD AND ON A STEEPER PART OF THE GLACIER IN DEEP SNOW AND TO THE LEFT OF THE USUAL TOUCHDOWN POINT.' ON LANDING THE GEAR BOXES BROKE, THE RIGHT SKI CAME OFF AND COLLIDED WITH THE RIGHT HORIZONTAL STABILIZER, AND THE PROPELLER CAME OFF THE ENGINE.