Cloudbursts and resulting landslides are likely to increase in future with rise in greenhouse gas emissions
Over the last three days, flash floods and cloudbursts have killed more than 20 people and caused widescale destruction.
Till July 17, 2022, a total of 1,098 lives have been lost across all the states and Union territories due to hydrometeorological disasters like cloudbursts and landslides. So, what are cloudbursts and why are they rising across India?
Cloudbursts are nothing but short-duration, intense rainfall events over a small area resulting in flood-like situations in the region. Not all instances of very heavy rainfall, however, are cloudbursts.
It is a cloudburst when the amount of rainfall in a particular region exceeds 100 millimetres in an hour, according to the India Meteorological Department definition.
As the minimum threshold is quite high, only 30 such incidents have been recorded between 1970 and 2016. This also means that a lot of reported cloudbursts in media are not actually cloudbursts by definition. That is because these events are highly localised.
However, some scientists term rainfall between 50 and 100 mm in a span of two hours a ‘mini cloudburst’. Cloudburst occurs when moisture-rich air travels up a mountainous region, forming a vertical column of clouds known as Cumulonimbus clouds.
The upward movement of these clouds provides the required energy for a cloudburst. According to studies, high relative humidity and cloud cover conditions fuel the formation of cloudburst events.
Most of these happen in the Himalayan states where the local topology, wind systems and temperature gradients between the lower and upper atmosphere facilitate the occurrence of such events. Even though cloudbursts are extremely localised events, the consequences of these events, are not confined to small areas.
The heavy downpours often trigger landslides and flash floods, causing extensive destruction downstream. As climate change is warming the oceans fast, the moisture-rich air reaches the Himalayan region accelerating the intensity and duration of cloudburst events.
The decadal temperature rise in the Himalayan region can also contribute to the rise in cloudbursts. Still, the trickiest part of all is that there is no satisfactory technique for anticipating the occurrence of cloud bursts as no weather agency can forecast the quantum of rainfall.
As greenhouse gas emissions increase, extreme reactions such as cloudbursts and resulting landslides are likely to increase in the coming years.
We are a voice to you; you have been a support to us. Together we build journalism that is independent, credible and fearless. You can further help us by making a donation. This will mean a lot for our ability to bring you news, perspectives and analysis from the ground so that we can make change together.
.png)
Comments are moderated and will be published only after the site moderator’s approval. Please use a genuine email ID and provide your name. Selected comments may also be used in the ‘Letters’ section of the Down To Earth print edition.