On 18 December 2022, an Airbus A330-200 in the cruise at FL400 in VMC was flown through the isolated top of a building convective cloud after its vertical development rate was underestimated and a short but severe turbulence upset and brief loss of control resulted. A few minutes earlier ATC had advised that “moderate to extreme precipitation and turbulence could be expected for the next 40 miles”. Cabin service was in progress and no prior warning was given which resulted in 24 unsecured cabin crew and passengers being injured, four seriously. Some cabin trim detached and some equipment was damaged.