Assessment and review of hydrometeorological aspects for cloudburst and flash flood events in the third pole region (Indian Himalaya)

Impacts of global climate change can be seen worldwide, both on developing and developed economies. In recent years, numerous researches have been carried out by the Government and Non-Government agencies in understanding, assessing, predicting, and responding to expected processes of global climate change and recommend policies for mitigation. Extreme weather events like increased precipitation, cloudbursts, flashfloods, and avalanches in the mountainous region threaten human lives, and state and national economies. In the Indian Himalayan Region (IHR), well distributed hydrometeorological records (contemporary and historical) that facilitate the understanding of processes driving extreme weather events are scarce or rarely available. However, the capacity to observe, measure and quantify precipitation on regional scales has increased tremendously over the last three decades. Topography of the IHR provides favorable conditions for the cloudburst phenomenon which lead to frequent flashfloods and landslides; killing hundreds of people every year. Understanding the exact mechanism of the driving processes of cloudbursts such as orographic lifting, precipitation distribution, precipitation thresholds and its source or origin are still uncertain. Keeping in view that cloudbursts have been increasing in both their frequency and intensity, they are likely to intensify in the near future. Present study analyzes and critically summarizes facts and impacts of cloudburst events through compilation of hydrometeorological records and analysis of available data in the IHR. Results indicate that natural climate variability has played a much greater role in driving these extreme events than earlier thought. A general consensus is observed about the role of climate change, large atmospheric circulations, teleconnections and landuse–landcover changes in driving these events. Therefore, in light of such challenges and potential research gaps, this paper aims at producing actionable knowledge in the IHR for climate modelers and policy planners to better serve the nation's needs.