CLOUD BURST
A cloudburst is an intense torrential rainfall brought by a thunderstorm that lasts for a relatively short duration (few minutes to few hours).
Cloudburst leads to flash floods and causes lot of damage to life and property.
Every intense rainfall is not a Cloudburst. Cloudburst specifically occurs when an air mass with high humidity is struck at a place due to various reasons.
- In 2010, South-Western strip of Russia (Caucasus Region, Moscow etc.) saw higher than normal temperatures (highest in in the last 100 years) and there were numerous cloudbursts in Jammu and Kashmir.
- A strong upper-atmospheric high was located over European Russia towards the beginning of summer.
- It diverted the jet stream (meandering of Sub-Tropical Jet Stream) and its rain-giving train (trough) of summer storms farther north than usual, giving much of Southern European Russia drought conditions.
- In addition, southern desert heat from central Asia, the Arabian Peninsula and North Africa began to flow northward, which strengthened this ridge of STJ and tightened its hold over the region.
Why do cloudbursts happen only in the mountains and hilly areas?
Cloudbursts do happen in plains as well, but there is a greater probability of them occurring in mountainous zones; it has to do with the terrain. Cloudbursts happen when saturated clouds are unable to produce rain because of the upward movement of very warm current of air. Rain drops, instead of dropping down, are carried upwards by the air current. New drops are formed and existing raindrops gain in size. After a point, the raindrops become too heavy for the cloud to hold on to, and they drop down together in a quick flash. Hilly terrains aid in heated air currents rising vertically upwards, thereby increasing the probability of a cloudburst situation. In addition, as pointed out earlier, cloudbursts get counted only when they result in largescale destruction of life and property which happens mainly in mountainous regions.
Can cloudbursts be forecast?
They are difficult to forecast but not impossible the difficulty arises out of the fact that they take place over a very small area. Forecasts for a very small area are difficult to predict. But through the use of doppler radar it is possible to forecast the possibility of cloudbursts about six hours in advance sometimes even 12-14 hours in advance. Unfortunately, there are no doppler radars installed in Himalayan states such as Uttarakhand and Himachal Pradesh.
Is the frequency of cloudbursts increasing?
There is a paucity of past data on cloudbursts in addition since only some of them get counted – only those that result in death and destruction – there is a problem of accuracy as well. But what is very clear is that events of extreme precipitation have been on the rise in the last few decades due to global warming; it is expected, keeping in mind that cloudburst events might be on the increase as well.