The recent spike in incidents of cloudbursts across various parts of India has drawn attention towards this weather phenomenon. Cloudbursts, categorized as intense, short-duration rainfall events over small areas, are known to exceed precipitation rates of 100mm per hour within a geographical region of approximately 20-30 square km. This article aims to offer an insight into what cloudbursts are, how they occur, their differentiation from regular rainfall, the effects of climate change on their frequency, their consequences, and the challenges in predicting them.
About Cloudbursts
Usually occurring when monsoon clouds drift northwards from the Bay of Bengal or Arabian Sea across the plains then onto the Himalayas, cloudbursts can sometimes result in as much as 75 millimetres of rain per hour. The atmospheric conditions play a crucial role in their occurrence – maximum levels of relative humidity and cloud cover, coupled with low temperature and slow winds allow for rapid condensation of a high volume of clouds, leading to a cloudburst. Temperature rise further enables the atmosphere to hold increased moisture levels which precipitate as highly intense, short-duration rainfall, often causing flash floods in mountainous regions and urban floods in cities.
Distinguishing Cloudbursts from Regular Rainfall
Rain represents condensed water falling from a cloud, while a cloudburst is characterized as a sudden and heavy rainstorm. Cloudbursts are termed so for rainfall exceeding 100mm per hour. This natural phenomenon ensues unexpectedly, abruptly, and with significantly high intensity.
Climate Change Implications
Research studies have predicted a potential rise in the frequency and intensity of cloudburst incidences owing to climate change. The World Meteorological Organization in May 2021 indicated a 40% likelihood of the annual global average temperature rising 1.5°C above pre-industrial levels within the coming five years. It also anticipated a 90% chance for at least one year between 2021 and 2025 to surpass the warmest recorded year, 2016. The increasing number of cloudburst events in the Himalayan region particularly points towards this trend, given that decadal temperature rises in this area exceed the global rate of temperature increase.
Consequences of Cloudbursts
Cloudbursts often lead to severe consequences due to their unexpected nature and high rainfall intensity. These include flash floods, landslides, mudflows, and land caving, all of which can cause significant damage to property, infrastructure, and sometimes even loss of life.
Prediction Challenges
Predicting cloudburst events poses substantial challenges due to their rapid development over a short timeframe. Although detection of potential cloudburst likelihood requires a highly refined network of radars, this solution comes at a high cost. Currently, only areas likely to receive heavy rainfall can be identified on a short-range scale. Identifying such areas and the meteorological conditions favoring cloudburst occurrences can aid in minimizing the resulting damage.