Date: 201904
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Weather elements / visibility: Turbulence; 10
Light: Daylight
Aircraft: J3 Cub
Operator: Personal
Operating under: Part 91
Flight plan: VFR
Mission: Personal
Flight phase: Taxi
ATC / advisory: UNICOM ZZZ
Reporter organization: Personal
Reporter function: Single Pilot; Pilot Flying
Reporter qualification: Flight Crew Sport / Recreational
Human factors: Situational Awareness; Training / Qualification
Anomaly: Ground Event / Encounter Loss Of Aircraft Control; Inflight Event / Encounter Weather / Turbulence
Detector: Person Flight Crew
When detected: Taxi
Contributing factors: Human Factors; Weather
Primary problem: Weather

Narrative: After a 1.5 hour VFR solo pleasure flight I returned to land at my home airport. The airport ATIS reported winds calm and variable; visibility 10 miles and clear. There were no other aircraft in the traffic pattern. I entered the traffic pattern at a 45 degree angle for a standard right hand approach to Runway XX; turned onto my downwind leg and checked the wind sock; confirming calm winds.  The approach and landing on Runway XX was uneventful. After landing on Runway XX; I was back taxiing on Runway XY toward my home hanger when an extremely strong wind in excess of 18 knots swept across the runway from the right (280 degrees) causing the airplane to immediately weather vane to the right; into the wind. I put the stick hard over and applied left rudder but not fast enough. I was unable to maintain control and the Cub went off the narrow runway to the right. There is a shallow drainage culvert on the side of the runway and the airplane rolled down into the culvert which is was filled with heavy wet snow. The combination of the downward slope and heavy resistance of the wet deep snow on tires caused the nose to pitch down and pivot on the nose resulting in the airplane tail to come up and over in the wet snow. The one and only bush off the side of the runway caught the upper fuselage; keeping the tail off the snow. I stepped out of the airplane completely unharmed.With the help of my pilot neighbors; we retrieved the airplane and we pulled it into my hanger which was close by. Upon inspection; I found the spinner was damaged but surprisingly; the composite propeller; which is very delicate; did not have a scratch on it; probably because of the wet deep snow. I also saw damage to the fabric on the horizontal stabilizer. I have contacted local factory authorized repair facility and requested they pick up the airplane with a trailer from my hanger and bring it back to their facility for a thorough inspection and repairs before the airplane is flown again. WHAT I LEARNED FROM THIS INCIDENT AND CORRECTIVE PILOT TRAINING: The weather in the mountains near the border of Idaho and Wyoming is often extreme and difficult to predict; especially in [home area]. With over 1200 hours of tail wheel time and as a local resident; I should have been better prepared for a sudden violent change in the wind. This is not that unusual for this airport; especially in the early spring. I will do remedial cross wind landing and taxiing training with a local flight instructor. I will pay closer attention to the windsock while taxing in order to more quickly perceive a significant change in wind speed and direction. I will be sure to stay on the center line while taxing to allow more distance to correct for the unexpected gust.   I was lucky nobody was injured and the airplane suffered only relatively minor cosmetic damage. I must remain 100% alert even when taxing.




Synopsis: Pilot reported while taxiing off the runway; a gust of wind came and pushed the aircraft off into a culvert near the runway; flipping the aircraft over.