Extreme rainfall events over the Himalayas between 1871 and 2007

Abstract

Currently there is much discussion regarding the impact of climate change and the vagaries of the weather, in particular extreme weather events. The Himalayas form the main natural water resource of the major river systems of the Indian region. We present a brief review of the available information and data for extreme rainfall events that were experienced in different sectors of the Himalayas during the last 137 years (1871-2007). Across the entire Himalayas, from east to west, there are now 822 rainfall stations. There was an increase in the rainfall station network from 1947 onwards, especially in the Nepal and Bhutan Himalayas. Extreme oneday rainfall has been picked out for each station irrespective of the period for which data are available. The decadal distribution of these extreme one-day rainfalls shows that there is a considerable increase in the frequencies during the decades 1951-1960 to 1991-2000, whereas there is a sudden decrease in the frequencies in the present decade during 2001-2007, indicating the need to understand the response of the systems to global change and the associated physical and climatological changes. This is essential in terms of preserving this natural resource and to encourage environmental management and sustainable development of mountain regions. © 2011 IAHS Press.