On January 22, 2004, about 1230 Pacific standard time, a Beech F33A, N33HY, collided with the ground during takeoff from the Shoshone Airport (L61), Shoshone, California, and came to rest inverted. The certified flight instructor (CFI) was operating the borrowed airplane under the provisions of 14 CFR Part 91. The CFI sustained serious injuries, and the private pilot/owner undergoing instruction (PUI) was not injured. The airplane sustained substantial damage. The instructional flight was en route to North Las Vegas Airport (VGT), Las Vegas, Nevada, and was originating at the time. Visual meteorological conditions prevailed and no flight plan had been filed. In a written statement, the CFI reported that the airplane landed uneventfully at the Shoshone airport earlier that day. Based on the windsock, the winds were from 290 degrees at 15 to 24 knots, variable and gusty. The CFI and PUI went to lunch. After lunch, the windsock was indicating variable winds from 290 degrees. The CFI had a brief discussion with the student about downhill and downwind takeoffs. After a preflight, they taxied to runway 15. The airplane did not accelerate as expected, and the remaining runway was insufficient to abort. The CFI continued the takeoff, and "forced the aircraft to fly at a very, low airspeed." The CFI then extended the flaps 15 degrees to lower the stall speed. As the airplane touched down, the CFI was unsure if the tail touched down first. He reduced the power, and the nose gear collapsed. The tail of the airplane then came over the top, and the airplane came to rest inverted. Local residents near and at the airport indicated that the wind had been "on and off" all morning, and as high as 15 to 20 knots. The pilot believed that the wind picked up during the time of the preflight, to the takeoff roll. He did not recheck the windsock. The CFI noted no mechanical malfunctions with the airplane prior to the accident. To prevent future accidents the CFI recommended completing a final check on the wind direction, prior to starting the takeoff roll. In a telephone conversation, the PUI reported that he had recently purchased the airplane. He was becoming familiar with the airplane, and the CFI operated the airplane controls during the takeoff. The airplane was equipped with a "throw-over" yoke. The yoke was positioned to the left front. The PUI was seated in the right front. The Airport/Facility Directory indicated that runway 15/33 was 2,380 feet long and 30 feet wide.