Cessna 180 pilot reported a violent yaw during takeoff; due to rapidly changing wind velocity and direction; which resulted in a ground loop of the tailwheel aircraft. The pilot rejected the takeoff and the aircraft had minor wingtip damage with no injuries.

Narrative

Very experienced tailwheel and Cessna 180 pilot. Takeoff Rwy XX. Had flown previously during the day and prior days. I would characterize the wind as coming from a predominant direction but extremely variable in direction and velocity on different sections of the airport depending on localized convective and thermal activity due to solar heating. I had done multiple takeoffs and landings in the days prior where the wind socks were in major disagreement with the prevailing wind call from the tower and even saw windsocks showing varying wind conditions on different parts of the airfield at the same time. Looking at reported tower wind history bracketing the incident; the wind was reported variable between West to North between calm and gusting 26 knots and the density altitude was approaching 10;000 feet. At the time of the incident; the tower wind report favored a departure on Rwy XX. As the takeoff was commenced there was a violent left yaw like I had never experienced before. This yaw persisted throughout the initial portion of the takeoff roll. Full right rudder and wheel brake were not enough to bring the longitudinal axis of the aircraft back in line with runway centerline. A decision was made to abort the takeoff as continuing would have resulted in a more dangerous situation. The aborted takeoff resulted in a ground loop and minor damage to the wingtip. Post incident I observed a strong gusty wind from the West/Southwest at my location and on the windsock on the Rwy XX approach end in the vicinity of where the takeoff was commenced. This wind appeared to even favor a Rwy XY takeoff and I perceived that it resulted in a strong left quartering tailwind. I believe this wind again was a result of local conditions due to convective thermal activity on the airfield. These conditions may have not been apparent to control tower personnel based on their vantage point and the information they were receiving from their wind sensor location. Complicating factors were the large vertical stabilizer surface area on the Cessna 180 for the left crosswind to act upon and the compounding left turning tendencies of slipsteam; engine torque and gyroscopic moment that overpowered my control authority. The high density altitude may have also been a complicating factor. I was not able to perceive this hazardous wind prior to commencing the takeoff however I will be much more vigilant in the future looking for signs of the variable wind during these environmental conditions and/or may choose not to fly during these conditions. Regardless; the responsibility lies with the Pilot in Command to maintain aircraft directional control and the ultimate causal factor is my inability to do that in these conditions.