EXTREME RAINFALL AND LANDSLIDE RESPONSE OF THE HIMALAYAN ENVIRONMENT

Abstract

This dissertation is designed to understand the (1) characteristics of extreme rainfall events; (2) drivers of extreme events; and (3) associated landslide response in the Mandakini Catchment and its vicinity in the Indian Himalaya with 2013 disaster as the motivation. Evidence of statistically significant increasing trends in pre-monsoon and monsoon events were obtained at places where temples and sacred shrines are located that are visited by thousands of visitors and pilgrims each year. The influence of the negative phase of daily Arctic Oscillation on extreme monsoon events was discernable and was found to influence the storm development embedded within the Westerly Troughs. A better landslide susceptibility map is generated than contemporary maps which has led to a better understanding of the landslide response of the Himalayan environment to extreme rainfall events. The role of the antecedent rainfall in causing slope instability before the extreme event of 2013 is discernable.