An Extreme Hailstorm in Istanbul: July 27, 2017 Case

A number of severe storms hit the city of Istanbul on July 27, 2017, including a supercell with hail size up to 8+ cm, leaving a record-breaking damage to property. In addition to the very large hail, up to 40 m/sec wind gusts and flooding in many parts of the city is reported. 3 people are injured, 311 trees are uprooted, 162 roofs are blown up, and 2 minarets as well as 4 large winches in the harbor are snapped, thousands of cars, windows and walls of many buildings are damaged. More than 300 million dollars damage is estimated.

An observational and numerical study of the case will be presented. Radar data indicate that the storm cells had very complex mesoscale features. A merging storm just over the city center was responsible from the very large hail, and possibly series of downbursts, which resulted in most of the damage.