The London Tornado of 1091 is the earliest reported tornado in England, occurring in London on Friday, 17 October 1091. It has been reckoned by modern assessment as possibly a T8 on the TORRO scale (roughly equivalent to an F4 on the Fujita scale) making it potentially the strongest recorded tornado in the British Isles, although this estimate is based on reports written 30 years after the tornado. The church of St Mary-le-Bow in the city of London was badly damaged; four rafters 26 feet (7.9 m) long were driven into the ground so that only 4 feet (1.2 m) protruded above the surface. Other churches in the area were demolished, as were over 600 (mostly wooden) houses. For all the damage inflicted, the tornado claimed just two known victims from a population of about 18,000. The tornado is mentioned in chronicles by Florence of Worcester and William of Malmesbury, the latter describing it as "a great spectacle for those watching from afar, but a terrifying experience for those standing near".