With the frequency of cloudbursts events increasing over India’s Himalayan region and beyond, experts consider this to be direct evidence of the impact of climate change on weather systems.
These events that are often difficult to predict have occurred across Jammu, Kashmir, Himachal Pradesh, and Uttarakhand, dramatically increasing the threat of floods that have the capacity to devastate areas. So what do we know about cloudburst events and how are they linked to climate change? We explore
Cloudburst characterisation
According to the India Meteorological Department (IMD), cloudburst events are charecterised when the amount of rainfall in a particular region or location exceeds 100 millimetres per hour. While it is this threshold that sets cloudbursts apart from normal precipitation events, some scientists have deemed rainfall events with fifty and 100 millimetres over a two hours period as a ‘mini cloudburst’.
Cloudbursts’ links to climate change
As temperatures increase through the effect of climate, the atmosphere is able to hold more and more moisture, particularly over areas such as the tropical Indian Ocean. Such moisture-rich air then has a greater likelihood to lead to periods of short, intense rainfall events known as cloudbursts.
Notably, cloudburst events have also been linked to climate change’s disruptive effect on the Indian monsoon, a window that has long been fundamental to the economic and ecological livelihoods of millions across India. IMD Director-General Mrutunjay Mohapatra notes that when warm monsoon winds interact with cold winds, it leads to the formation of huge cumulonimbus clouds which can stretch to 13-14 kilometers in height. According to experts, these clouds have at times been responsible for these extreme periods of heavy precipitation over short periods of time.
Cloudbursts increasing in frequency
According to several studies, these links to climate change show that cloudburst weather events will increase in frequency and intensity worldwide. With climate change creating favourable conditions for cloudburst formation, the World Meteorological Organization predicts there is a ninety per cent likelihood of at least one event per year between 2021 and 2025.
Cities vulnerability to cloudbursts
As with other climate change weather exacerbated events, certain locations are often less well-equipped to manage and mitigate the effects. With regards to cloudburst weather events, researchers have identified cities as areas that struggle to deal with short durations of intense rainfall.
This is partially because conventional stormwater and flood management methods do not have the adequate means to drain the level of rainfall that occurs with such events. With cloudburst events increasing in frequency, it is projected that cities will need to rapidly transform their systems, infrastructure decisions, and policies.
To better mitigate such events in the future, researchers have also suggested cities share their toolbox of plans with one another as cloudburst effect locations from Copenhagen to Kashmir.
Researchers link cloudburst particles to forest fires
As one of the less predictable effects, researchers found that the formation of the tiny particles on which water vapor condenses called cloud condensation nuclei (CNN) could be linked to the occurrence of forest fires on the Indian subcontinent.
“We have observed that whenever there is rainfall, the CNN is low. Also, during the forest fires episode, we found CNNi to be five times more than normal. The five times CNN concentration might contribute to the formation of the cloud and also, the formation of rain droplets in the atmosphere,” said Alok Sagar Gautam, lead author of the study. “It won’t disappear immediately, but will show its impact on the weather as well. After forest fires, if we witness excessive rainfall, it might be due to the higher CCN concentration in the atmosphere.”
