Cloud Bursting Over Leh Presented By:- Manish Ranjan Singh IMED, Pune
Contents• An Overview about Cloud Bursting• Flash Flood• Effects Of Flash Flood• 2010 Leh Flash Flood• Aftermath Of the disaster• Relief/Rescue efforts• Ways to prevent and control Flash Flood• Flood Safety measures• References
Overview About Cloud Bursting• A cloudburst is sudden copious rainfall. It is a sudden aggressive rainstorm falling for a short period of time limited to a small geographical area.• Meteorologists say the rain from a cloudburst is usually of the shower type with a fall rate equal to or greater than 100 mm (3.94 inches) per hour.• Generally cloudbursts are associated with thunderstorms. The air currents rushing upwards in a rainstorm hold up a large amount of water. If these currents suddenly cease, the entire amount of water descends on to a small area with catastrophic force all of a sudden and causes mass destruction. This is due to a rapid condensation of the clouds.
• They occur most often in desert and mountainous regions, and in interior regions of continental landmasses.• During a cloudburst, more than 20 mm of rain may fall in a few minutes. They are called bursts probably because it was believed earlier that clouds were solid masses full of water. So, these violent storms were attributed to their bursting.• When there are instances of cloudbursts, the results can be disastrous. Cloudburst is also responsible for Flash flood creation.
Flash Flood• A flash flood is a rapid flooding of low-lying areas — washes, rivers, dry lakes and basins.• It may be caused by heavy rain associated with a storm, hurricane, or tropical storm or meltwater from ice or snow flowing over ice sheets or snowfields.• Flash floods are distinguished from a regular flood by a timescale less than six hours.• Cloud bursting is one of the other causes to Flash Flood. As it occurs within minutes or few hours of excessive rainfall.
Effects of Flash FloodPrimary Effect:• Physical damage- Can range anywhere from bridges, cars, buildings, sewer systems, roadways, canals and any other type of structure• Casualties- People and livestock die due to drowning. It can also lead to epidemics and diseases.Secondary Effect:• Water supplies- Contamination of water. Clean drinking water becomes scarce• Diseases- Unhygienic conditions. Spread of water-borne diseases• Crops and food supplies- Shortage of food crops can be caused due to loss of entire harves
Territory/Long term Effects• Economic- Economic hardship, due to temporary decline in tourism,• Rebuilding costs• Food shortage leading to inflation, etc.
2010 Leh Flash FloodKey facts about Disaster:• Duration: 6 August 2010• Fatalities: at least 255 killed, 29 missing• Damages: Rs 133 cr.• Areas Affected: Leh, and numerous other villages in Ladakh range
• The 2010 Ladakh floods occurred on 6 August 2010 across a large part of Ladakh, a region of the northern most Indian state of Jammu and Kashmir.• The flash floods happened after a night of heavy downpour. The cloudburst itself occurred between 00:00–00:30 hours IST on 6 August 2010, leading to flash flooding, debris flows, and mudslides over the region.• The most intense part of the storm was focused in a 6 km wide band parallel to, and a few kilometers from, the river Indus.• Some estimates of the maximum total rainfall in some places were as high as 250 mm, and at least 150 mm/h over Leh during the most intense part of the storm.
Aftermath of the Disaster• The rains occurred at night, and surprised everyone. In Leh, many buildings were destroyed including hospitals, the bus terminal, radio station transmitter, telephone exchange and mobile-phone towers.• 71 towns and villages were damaged, including the main town in the area, Leh.• Overall, 9000 people were directly affected by the event.• At least 255 people are reported to have died, six of whom were foreign tourists, after a cloud burst and heavy overnight rains triggered flash floods, mudslides, and debris flows.
• 200 people were reported missing in the initial aftermath of the storm, and thousands more were rendered homeless after the flooding caused extensive damage to property and infrastructure.• BSNL communication systems were fully destroyed. Communications were later restored by the Indian Army.• The local bus station was severely damaged and some of the buses were carried more than a mile by the mud.• The citys airport was damaged but was rapidly repaired to allow relief flights the following day.• In total, almost 1500 homes in 71 settlements across the area were reported to have been damaged.
Relief/Rescue Efforts• The rescue efforts were hampered by gushing water and mud which was 10 feet high in places. In addition many of the roads and bridges leading to Leh were damaged making it difficult to truck in relief supplies.• Four hundred critically wounded people were evacuated and some were admitted to the army hospital in Leh. Indian Army soldiers launched a massive rescue operation.• Home minister P.Chidambaram said that over 6000 security personnel were deployed in Leh for rescue operations. Prime minister Manmohan Singh expressed grief and announced compensation of Rs. 1 lakh to the kin of deceased and Rs. 50,000 for those injured.• Chief Minister of the state Omar Abdullah directed the administration to undertake relief effort on a war footing.
Ways To Prevent and Control Flash Flood• Flood-control dams are constructed throughout across rivers.• Dikes and levees are built alongside rivers to keep them from overflowing during periods of high water• Canals are also used to help drain off extra water. Streams and rivers can be diverted to avoid highly populated areas.• Regulation of floodplain development and urbanization would reduce flood losses.• Prevention of soil erosion.• Plant lots of trees, treat slopes and grads, and create reservoirs to catch sediment and debris.
Flood Safety• Stay out of areas subject to flooding. Dips, low spots, canyons, washes, etc., can become filled with water• If outdoors, climb to high ground and stay there. Move away from dangerous flood waters• If you come upon a flowing stream where water is above your ankles, stop, turn around, and go another way• Never try to walk, swim, or drive through such swift water.