Uttarakhand: A Hotspot for Extreme Events?

Abstract

This study investigates the spatial and temporal climate variability, particularly focusing on extreme hydrometeorological events, over Uttarakhand, India. Located within the Central Himalaya, the region is characterised by frequent extreme rainfall events during the Indian Summer Monsoon (ISM) and winter western disturbances (WDs). To understand the relationship between climate variability and global teleconnections (North Atlantic Oscillation (NAO), El Niño-Southern Oscillation (ENSO), Dipole Mode Index (DMI), we analysed four decades (1982–2020) of observational data, including rainfall, surface radiative temperature, and surface runoff, alongside teleconnection indices. A composite analysis of 140 hydro-meteorological events is performed to correlate climate variations. The results demonstrate significant spatial variability in rainfall and surface runoff between western and eastern Uttarakhand. A marked increase in extreme events, particularly during the monsoon season, is observed after 2010. Notably, the period 1998-2009 shows increased annual temperatures and decreased precipitation and surface runoff, coinciding with periods of low amplitudes in the considered global teleconnections.