Cloudburst: a sudden, very heavy rainfall, usually local in nature and of brief duration. Short spells of very heavy rainfall over a small geographical area can cause widespread  destruction.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 millimetres of rain per hour
Not all instances of very heavy rainfall, however, are cloudbursts. A cloudburst has a very specific definition.
Most so-called cloudbursts occur in connection with thunderstorms. In these storms there are violent uprushes of air, which at times prevent the condensing raindrops from falling to the ground. A large amount of water may thus accumulate at high levels, and if the upward currents are weakened the whole of this water falls at one time.
Cloudbursts are not uncommon events, particularly during the monsoon months.
It occurs mainly in mountainous areas when the warm air currents rise from the ground towards clouds. It carries the falling raindrops along with it. Thus, the rainfall fails to occur steadily, and the clouds have excessive condensation. There is also an accumulation of a large amount of water at high altitudes. The warm air from below restricts the fall of water. The upward current becomes weak, and the waterfalls on a single stretch. The requisite energy for the downpour comes from the movement of air upwards. Generally, cloudbursts occur at an elevation of 1000 to 2500 meters above sea level. Cumulonimbus clouds are responsible for the heavy downpour. In cloudbursts, smaller droplets of water coagulate with smaller ones and result in the Langmuir precipitation process (the process in which large droplets of rain coagulate with tiny droplets of rain, which fall down slowly.)
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.
These events are highly localized and they take place in very small areas which are often devoid of rainfall measuring instruments.
Cloudbursts are especially common in mountainous areas. This is probably because the warm air currents of a thunderstorm tend to follow the upward slope of a mountain. The effects of heavy rain are especially striking on mountain slopes because the falling water is concentrated in valleys and gulleys. Mountain cloudbursts cause sudden and destructive floods. The intensity of rainfall in the most severe cloudbursts can only be conjectured.
Continuous and violent rainfall can result in heavy floods that can be dangerous.
It also causes-Debris flows,Landslides,Mudslides,
Flooding,Mass Movements,Drownings,Road
closures and cloudburst Accidents.
Cloudbursts in hilly terrains can be disastrous and cause massive destruction to life and property as most of the water gets concentrated in the valleys and gullies.
It can cause damage to the flora and fauna of the particular area and public utilities.
There is no long-term trend that suggests that cloudbursts, as defined by the IMD, are rising.
However, incidents of extreme rainfall, as also other extreme weather events, are increasing — not just in India but across the world.
While the overall amount of rainfall in India has not changed substantially, an increasing proportion of rainfall is happening in a short span of time.
That means that the wet spells are very wet, and are interspersed with prolonged dry spells even in the rainy season.
This kind of pattern, attributed to climate change, does suggest that cloudburst events might also be on the rise.
Since they are not predictable and take place over a small area, it is advisable to take necessary precautions before the cloudburst. Cloudburst can result in flash floods that can wash out everything in a matter of time. A constant update on the weather is highly recommended with early warning and decision support systems. In hilly areas, weather warnings can give ample time for mitigation, and thereby shifting to a safe shelter can be possible.
Doppler’s radar, used for weather forecasting, can also be used to detect the possibility of a cloudburst. The chances of a cloudburst can be predicted six hours in advance. But they are expensive.
Identifying areas of heavy rainfall can do a lot in evading the danger and minimizing the damage.
Inhabitation of low-lying areas should also be reduced.