Analysis of the severe flood of 13t-16th October 2000 in Piedmont (Italy)

Abstract

During the 13th-16th of October 2000 a disastrous flood occurred in the whole Piedmont associated with heavy rainfall over the North-Western Alpine chain in successive episodes spanning the whole period. The event was originated by a Southern, strong and moist, upper flow established over North-Western Italy, associated at lower layers with an eastern rotation of the air flow and consequently strong convergence on the western Po Valley. The high temperature of the Mediterranean Sea caused a high rate of moisture enrichment of the air mass moving towards Piedmont. The most intense rainfall (values larger than 600 mm in 96 hours have been re ported) occurred over the mountainous regions, where the high temperatures forced the snow-rain threshold at very high altitudes. This event was one of the most intense events of the last 200 years in the Piedmont area. The majority of the basins suffered strong flood episodes; most of the mountainous portion of the basins and also part of the city of Turin down the Po Valley were seriously damaged by the strong rainfalls.