The pilot was landing a wheel/ski equipped airplane on a frozen, wind-blown, ice and snow-covered lake. He had established a landing area earlier in the day, by laying down ski tracks with a friends ski equipped airplane. Upon touchdown, the airplane did not slow as expected, and it began to veer off the proposed landing area. While attempting to correct for the veer, the right ski struck a hole hidden underneath the snow and ice, and the right main landing gear leg separated from the airplane. The airplane sustained substantial damage to the right wing and aileron. The pilot reported no preaccident mechanical malfunctions or failures with the airplane that would have precluded normal operation.