On January 13, 2007, about 1800 Alaska standard time, a ski-equipped, Piper PA-18 airplane, N237WT, sustained substantial damage following a loss of directional control during takeoff, about 28 miles west-northwest of Tyonek, Alaska. The airplane was being operated by the pilot as a visual flight rules (VFR) personal cross-country flight under Title 14, CFR Part 91, when the accident occurred. The solo, private certificated pilot was not injured. Visual meteorological conditions prevailed, and no flight plan was filed. During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC) on January 15, the pilot said he had landed the ski-equipped airplane in a snow-covered meadow. He said prior to landing he had set down tracks, and determined the area was suitable for landing. The pilot said after landing, the airplane sank into the snow, and came to a abrupt stop. He said the snow conditions were not what he had expected. He dug the airplane out, and packed down an area around the airplane with his snowshoes. He indicated he packed down a takeoff area, and removed as much gear from the airplane as possible to lighten the takeoff load. During the takeoff roll the pilot said the airplane veered off the packed area, burying the right ski and wing in the snow. After he dug the airplane out, he saw the wing and propeller were damaged. The airplane was taken by helicopter to its home airport, and surveyed by a mechanic. During a telephone conversation with the NTSB IIC, the mechanic said both the fore and aft main spars in the right wing would have to be replaced. The pilot did not submit a Pilot/Operator Aircraft Accident/Incident Report. The airplane was not examined by the NTSB.