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Four people were killed and 49 missing following multiple incidents of cloudburst in Shimla, Mandi,and Kullu districts of Himachal Pradesh, where torrential rain has left several rivers in a spate.
Thirty-three people went missing after a cloudburst led to a flash flood in the Samej area, near Jhakri hydro project
Cloudbursts
Cloudbursts are short-duration, intense rainfall events over a small area.
It is a weather phenomenon with unexpected precipitation exceeding 100mm/h over a geographical region of approximately 20-30 square km.
In the Indian Subcontinent, it generally occurs when a monsoon cloud drifts northwards
from the Bay of Bengal or the Arabian Sea across the plains then on to the Himalaya that sometimes brings 75 mm of rain per hour
The relative humidity and cloud cover is at the maximum level with low temperature
Slow winds because of which a high amount of clouds may get condensed at a very rapid rate and result in a cloudburst.
Flash floods
These are sudden surges in water levels generally during or following an intense spell of rain.
These are highly localised events of short duration with a very high peak and usually have less than six hours between the occurrence of the rainfall and peak flood.
The flood situation worsens in the presence of choked drainage lines or encroachments obstructing the natural flow of water.
It may be caused by heavy rain associated with a severe thunderstorm, hurricane, tropical storm, or meltwater from ice or snow flowing over ice sheets or snowfields.
Flash Floods can also occur due to Dam or Levee Breaks, and/or Mudslides (Debris Flow).
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