A Comprehensive Study of June 6, 1992 Storm in Mashhad

An intense storm occurred on June 6, 1992 in Mashhad city and its suburb, which caused a flood in the residential areas of Najafi, Chahar-cheshmeh and Nodareh. As a consequence of the abnormally huge flood, 25 people lost their lives and many structures were destroyed. Three recording rain gages located in Mashhad city (airport, College of Agriculture, and Water Authority) and one in the suburbs (Toroq dam) recorded the temporal distribution of the storm. Twenty five other nearby rain gages in the region also recorded the event. The rainfall hyetographs and rainfall amounts were analyzed. The results of this survey showed that: a) maximum rainfall intensity over a 15-minute duration in the College of Agriculture station, one of the centers of the storm, was 112 mm/hr, b) temporal distribution of rainfall for all recording stations were nearly the same, c) these patterns were in close agreement with all historic storms, and d) a return period of 380 years was implied via comparing the maximum rainfall intensity with relevant IDF curves. As a consequence, although an intense storm had happened, it was simply an outlier.