On January 8, 2004, at approximately 1400 mountain standard time, a Piper PA-18-150, N57534, was substantially damaged when it nosed over during landing at Pinyon Air Park (CO43), Glade Park, Colorado. The private pilot, the sole occupant on board, was not injured. Visual meteorological conditions prevailed. The personal, cross-country flight was being conducted under the provisions of Title 14 CFR Part 91. No flight plan had been filed for the flight that departed Blanding, Utah, at approximately 1230. According to the accident report submitted by the pilot, he was en route to Grand Junction, Colorado. Due to low clouds and visibility in Grand Junction, the pilot diverted to Pinyon Air Park. While circling for landing, the pilot noted that the field was snow covered; however, he could see vegetation through the snow and bare ground where snowmobiles had made several turns. During the landing, the main landing gear sank in the deep snow and the airplane nosed over. The vertical stabilizer and rudder was crushed and the left wing was bent.