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A cloudburst is an extreme amount of precipitation in a short period of time, mm of precipitation corresponds to 25,000 metric tons/km2 (1 inch corresponds to 72,300 short tons over one square mile). However, cloudbursts are infrequent as they occur only via orographic lift or occasionally when a warm air parcel mixes with cooler air, resulting in sudden condensation. At times, a large amount of runoff from higher elevations is mistakenly conflated with a cloudburst. The term "cloudburst" arose from the notion that clouds were akin to water balloons and could burst, resulting in rapid precipitation. Though this idea has since been disproven, the term remains in use.sometimes accompanied by hail and thunder, which is capable of creating flood conditions.Cloudburst can suddenly dump large amounts of water e.g. 25
Rainfall rate equal to or greater than 100 millimetres (3.9 in) per hour is a cloudburst. However, different definitions are used, e.g. the Swedish weather service SMHI defines the corresponding Swedish term "skyfall" as 1 mm/min for short bursts and 50 mm/h for longer rainfalls. The associated convective cloud can extend up to a height of 15 kilometres (9.3 mi) above the ground.
During a cloudburst, more than 20 millimetres (0.79 in) of rain may fall in a few minutes. The results of cloudbursts can be disastrous. Cloudbursts are also responsible for flash flood creation.
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. 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.
|1 minute||1.5 inches (38.10 mm)||Basse-Terre, Guadeloupe||26 November 1970|
|5.5 minutes||2.43 inches (61.72 mm)||Port Bell, Panama||29 November 1911|
|15 minutes||7.8 inches (198.12 mm)||Plumb Point, Jamaica||12 May 1916|
|20 minutes||8.1 inches (205.74 mm)||Curtea de Argeș, Romania||7 July 1947|
|40 minutes||9.25 inches (234.95 mm)||Guinea, Virginia, United States||24 August 1906|
|1 hour||9.84 inches (250 mm)||Leh, Jammu and Kashmir, India||August 5, 2010|
|1 hour||5.67 inches (144 mm)||Pune, Maharashtra, India||September 29, 2010|
|1.5 hours||7.15 inches (182 mm)||Pune, Maharashtra, India||October 4, 2010|
|5 hours||15.35 inches (390 mm)||La Plata, Buenos Aires, Argentina||April 2, 2013|
|10 hours||57.00 inches (1,448 mm)||Mumbai, Maharashtra, India||July 26, 2005|
|24 hours||54.00 inches (1,372 mm)||Pithoragarh, Uttarakhand, India||July 1, 2016|
|13 hours||45.03 inches (1,144 mm)||Foc-Foc, La Réunion||January 8, 1966|
|20 hours||91.69 inches (2,329 mm)||Ganges Delta, Bangladesh/India||January 8, 1966|
|24 hours||73.62 inches (1,870 mm)||Cilaos, La Réunion||March, 1952|
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 uplands adjacent to the Front Range of Colorado and the streams which drain the Front Range are subject to occasional cloudbursts and flash floods. This weather pattern is associated with upslope winds bringing moisture northwestward from the Gulf of Mexico.
A flash flood is a rapid flooding of low-lying areas: washes, rivers, dry lakes and depressions. 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 may occur after the collapse of a natural ice or debris dam, or a human structure such as a man-made dam, as occurred before the Johnstown Flood of 1889. Flash floods are distinguished from regular floods by having a timescale of fewer than six hours between rainfall and the onset of flooding. The water that is temporarily available is often used by plants with rapid germination and short growth cycles and by specially adapted animal life.
Karachi has an arid climate, albeit a moderate version of this climate. Karachi is located on the coast and as a result has a relatively mild climate. Karachi has two main seasons; Summer & Winter, while spring and autumn are very short. Summer season persists for longest period during the year.Karachi also receives the monsoon rains from July to September. The city enjoys a tropical climate encompassing warm winters and hot summers. The humidity levels usually remain high from March to November, while very low in Winter as the wind direction in winter is North Easterly.
Pakistan recorded one of the highest temperatures in the world – 53.5 °C (128.3 °F) – on 26 May 2010, the hottest temperature ever recorded in Pakistan and also the hottest measured temperature ever recorded on the continent of Asia. As Pakistan is located on a great landmass north of the Tropic of Cancer, it has a continental type of climate characterized by extreme variations of temperature, both seasonally and daily. Very high altitudes modify the climate in the cold, snow-covered northern mountains; temperatures on the Balochistan Plateau are somewhat higher. Along the coastal strip, the climate is modified by sea breezes. In the rest of the country, temperatures reach great heights in the summer; the mean temperature during June is 38 °C (100 °F) in the plains, the highest temperatures can exceed 47 °C (117 °F). In the summer, hot winds called Loo blow across the plains during the day. Trees shed their leaves to avoid loss of moisture. The dry, hot weather is broken occasionally by dust storms and thunderstorms that temporarily lower the temperature. Evenings are cool; the daily variation in temperature may be as much as 11C to 17C. Winters are cold, with minimum mean temperatures in Punjab of about 4 °C (39 °F) in January, and sub-zero temperatures in the far north and Balochistan.
Lai Nullah, commonly called Nullah Lai, is a rain water fed natural stream flowing through the city of Rawalpindi. Every monsoon season the stream floods after being fed by its catchment basin in the Margalla Hills bordering Islamabad, Pakistan.
The climate of Islamabad is a humid subtropical climate (Köppen climate classification, with five seasons: Winter, Spring, Summer, Rainy Monsoon and Autumn. The hottest month is June, where average highs routinely exceed 38 °C. The wettest month is July, with heavy rainfall and evening thunderstorms with the possibility of cloudburst. The coolest month is January, with temperatures variable by location. In Islamabad, temperatures vary from cold to mild, routinely dropping below zero. In the hills there is sparse snowfall. The weather ranges from a minimum of −3.9 °C in January to a maximum of 46.1 °C in June. The average low is 2 °C in January, while the average high is 38.1 °C in June. The highest temperature recorded was 46.5 °C in June, while the lowest temperature was −4 °C in January. On 23 July 2001, Islamabad received a record breaking 620 millimetres of rainfall in just 10 hours. It was the heaviest rainfall in 24 hours in Islamabad and at any locality in Pakistan during the past 100 years. Following is the weather observed over Islamabad Airport, which is actually located in Rawalpindi.
The 2010 China floods began in early May 2010. Three hundred and ninety-two people died, and a further 232 people were reported missing as of June 30, 2010, including 57 people in a landslide in Guizhou. Fifty-three of the deaths occurred from the flooding and landslides between May 31 and June 3, and 266 deaths occurred between June 13 and June 29. Four hundred and twenty four people were killed by the end of June, including 42 from the Guizhou landslide; 277 more were killed and 147 left missing in the first two weeks of July, bringing the death toll as of August 5 to 1,072. A landslide in early August in Gansu killed at least 1,471 people and left 294 missing. In total, the flooding and landslides killed at least 3,185 people in China by August 31. More than 230 million people in 28 provinces, municipalities and regions, especially the southern and central provinces and regions of Zhejiang, Fujian, Jiangxi, Hubei, Hunan, Guangdong, Guangxi, Chongqing Municipality, Gansu, Sichuan and Guizhou, and the northeastern province of Jilin were affected, while at least 4.66 million people were evacuated because of the risk of flooding and landslides in the latter half of June. By early August, over 12 million people were evacuated, and that number rose to 15.2 million by August 31.
The 2010 Ladakh floods occurred on 6 August 2010 across a large part of Ladakh, a region in the northernmost Indian state of Jammu and Kashmir. 71 towns and villages were damaged, including the main town in the area, Leh. At least 255 people are reported to have died, six of whom were foreign tourists, after a cloudburst and heavy overnight rains triggered flash floods, mudflows, 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. Overall, 9000 people were directly affected by the event.
Lahore features a five-season semi-arid climate (from another source: Composite monsoon climate) with five seasons: foggy winter with few western disturbances causing rain; pleasant spring ; summer with dust, rain storms and heat wave periods; rainy monsoon ; and dry autumn.
Multan is located in the southern part of Punjab, province in Pakistan.Multan features an arid climate with very hot summers and cold winters. The city witnesses some of the most extreme temperatures in the country.Dust storms are a common occurrence within the city. The closest major city is Bahawalpur. The area around the city is a flat plain and is ideal for agriculture, with many citrus and mango farms. There are many canals that cut across the Multan District, providing water from nearby farms. This makes the land very fertile. However usually land close to the Chenab River are flooded in the monsoon season.
The climate of Hyderabad features an arid climate. The days are hot and dry, usually going up to extreme highs of 40 °C (104 °F), while the nights are cool and breezy. Winds usually bring along clouds of dust, and people prefer staying indoors in the daytime, while the breezes at night are pleasant and clean.
Dhaka experiences a hot, wet and humid tropical climate. Under the Köppen climate classification, Dhaka has a tropical wet and dry climate. The city has a distinct monsoonal season, with an annual average temperature of 25 °C (77 °F) and monthly means varying between 18 °C (64 °F) in January and 29 °C (84 °F) in August. Nearly 80% of the annual average rainfall of 1,854 millimetres (73.0 in) occurs during the monsoon season which lasts from May until the end of September. Increasing air and water pollution emanating from traffic congestion and industrial waste are serious problems affecting public health and the quality of life in the city. Water bodies and wetlands around Dhaka are facing destruction as these are being filled up to construct multi-storied buildings and other real estate developments. Coupled with pollution, such erosion of natural habitats threatens to destroy much of the regional biodiversity.
The 2011 Balochistan floods started from the last week of February and continued until the first week of March. Balochistan province was already badly affected from last year's devastating floods as UNHCR claims that 166,000 flood victims are still homeless in the province with 240 people still living in camps.
On 23 July 2001, Islamabad experienced a record breaking 620 millimetres (24 in) of rainfall, which was the 24 hours heaviest rainfall in Pakistan during the past 100 years. Continuous downpour lasted for about 10 hours from 0600 to 1600 PST in Islamabad and Rawalpindi, caused the worst ever Flash flood in the local stream called Nulla Lai and its tributaries of Rawalpindi, which not only flood the low-lying areas of the twin cities but swept away the banks of the stream and buildings built in the encroachments. Islamabad's twin city, Rawalpindi experienced 335 millimetres (13.2 in) of rain during this event.
The 2011 China floods are a series of floods from June to September 2011 that occurred in central and southern parts of the People's Republic of China. They were caused by heavy rain that inundated portions of 12 provinces, leaving other provinces still suffering a prolonged drought, a total of over 36 million people have been affected, killing at least 355 and with direct economic losses of nearly US$6.5 billion.
The 2011 Sindh floods was the highest-ever recorded rainfall between 11 August 2011, and 14 September 2011 in Sindh Province, Pakistan.
Rawalpindi features a humid subtropical climate with long and hot summers, a monsoon and short, mild and wet winters. Its climate is classified as very similar to its twin city Islamabad, but the geographical location and extreme urbanization of Rawalpindi has led to weather and climatic conditions that are notably different from its twin. Rawalpindi's weather has historically been known to change rather quickly due to its proximity to Himalayas and the Pir Panjal Range. These mountains not only influence the weather of the city, but also provide great recreation during the hot months. Furthermore, Its warm comfortable mean annual temperature of 21.3 °C (70 °F) attracts people to live here permanently from all over Pakistan. The average annual rainfall is abundant at 1,346.8 millimetres (53.02 in), most of which falls in the monsoon season. However, frontal cloud bands also bring significant rainfall in the winter. In summers, June is the hottest with record maximum temperature at a blistering 48.3 °C (119 °F) recorded on 13 June 1953. On the other hand, January is the coldest month of the year when temperature can drop to a minimum −3.9 °C (25 °F) in the winter recorded on 17 January 1967. Throughout the year, Rawalpindi and Islamabad experience an average of about 98 thunderstorms, which is the highest frequency of thunderstorms in Punjab province of any plane station. In fact, most rainfall in the city is accompanied by a thunderstorm with peak activity experienced in August. Record rainfall was experienced in the year 2013 at a massive 1,988 millimetres (78.3 in) mostly due to an unusually wet monsoon season. On a typical day, the city hosts breezy afternoons, but usually calm to light breeze wind conditions are observed after midnight. The mean annual wind speed of Rawalpindi is roughly 10 kilometres per hour (6.2 mph) at 14 m height. Moreover, just a few kilometers southwest of Rawalpindi, the potential power generation has been identified by U.S. Aid to be between marginal to good at 50 m height.
Floodings occur when an extreme volume of water is carried by rivers, creeks and many other geographical features into areas where the water cannot be drained adequately. Often, during times of heavy rainfall, drainage systems in residential areas are not adequate or unchecked civil development severely impedes the functionality of an otherwise acceptable drainage system. Floods cause extremely large numbers of fatalities in every country, but due to India's extremely high population density and often under development standards, a large amount of damages and many deaths occurred. India witnesses flood due to excessive rain which then results in overflow of rivers, lakes and dams, which adds to cause large amounts of damage to people's lives and property. In the past, India has witnessed many of the largest, most catastrophic floods, causing irreparable damage to people's livelihood, property, and crucial infrastructure.
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