On August 17, 1998, a massive landslide following heavy rain and a cloudburst at Malpa village killed 250 people, including 60 Kailash Mansarovar pilgrims in Kali valley of the Pithoragarh district, Uttarakhand.On August 15, 1997, 115 people were killed when a cloudburst occurred and trail of death was all that was left behind in Chirgaon in Shimla district, Himachal Pradesh.Alaknanda River in Uttarakhand and its entire river basin, from Hanumanchatti near the pilgrimage town of Badrinath to Haridwar was affected. However, around 400 pilgrims route to Badrinath, were saved due to the alertness of a police constable who guided them to run uphill. In addition, a roadside settlement between Pipalkoti and Helong called Belakuchi in the Alaknanda valley was washed away along with a convoy of 30 buses, by the roaring Alaknanda river.
The catastrophe was so large that it wiped out the leftover of the 1894 Gohna lake. According to an estimate, floods transported about 15.9 × 106 tonnes of sediment within a day6. In July 1970, the Alaknanda valley witnessed a major flood, This was attributed to a cloudburst on the night of 20 July 1970 on the southern mountain front in the Alaknanda valley (between Joshimath and Chamoli).About 15,000 people died and around 80,000 houses were destroyed along the banks of the river. On Septem– A cloudburst resulted in a flood where the Musi River swelled up to 3.4 meters.On September 27, 2020, record breaking 433 millimetres (17.0 in) of rain fell just in 12 hours in the city of Rangpur in Northern Bangladesh, producing widespread flooding across the city.On Ja record breaking 333 millimetres (13.1 in) of rain was recorded in Dhaka, in 24 hours, previously 326 millimetres (12.8 in) of rain was recorded on July 13, 1956.On J425 millimetres (16.7 in) mm of rain fell in 24 hours in Chittagong.In September, 2004 341 millimetres (13.4 in) mm of rain was recorded in Dhaka in 24 hours.In the Indian subcontinent, a cloudburst usually occurs when a monsoon cloud drifts northwards, from the Bay of Bengal or Arabian Sea across the plains, then onto the Himalayas and bursts, bringing rainfall as high as 75 millimetres per hour. The skillful forecasting of rainfall in hilly regions remains challenging due to the uncertainties in the interaction between the moisture convergence and the hilly terrain, the cloud microphysics, and the heating-cooling mechanisms at different atmospheric levels. Weather forecast models also face a similar challenge in simulating the clouds at a high resolution. While satellites are extensively useful in detecting large-scale weather systems and rainfall, the resolution of the precipitation radars of these satellites are usually smaller than the area of cloudbursts, and hence they go undetected. It is not essential that cloudbursts occur only when a cloud clashes with a solid body like a mountain, they can also occur when hot water vapor mingles into the cold resulting in sudden condensation.ĭetecting and Forecasting Cloudbursts Rapid precipitation from cumulonimbus clouds is possible due to the Langmuir precipitation process in which large droplets can grow rapidly by coagulating with smaller droplets which fall down slowly. Cloudbursts are also responsible for flash flood creation. The results of cloudbursts can be disastrous. ĭuring a cloudburst, more than 20 millimetres (0.79 in) of rain may fall in a few minutes. The associated convective cloud can extend up to a height of 15 kilometres (9.3 mi) above the ground. the Swedish weather service SMHI defines the corresponding Swedish term "skyfall" as 1 millimetre (0.039 in) per minute for short bursts and 50 millimetres (2.0 in) per hour for longer rainfalls. However, different definitions are used, e.g. Rainfall rate equal to or greater than 100 millimetres (3.9 in) per hour is a cloudburst. 2 Detecting and Forecasting Cloudbursts.