2001 Islamabad Cloudburst
Date of Occurrence	23 July 2001
Place	Islamabad, Rawalpindi, Hazara and Malakand Divisions
Deaths	61
Maximum Precipitation	620 millimetres (24.4 in), in Islamabad

On 23 July 2001, Islamabad

Islamabad

Islamabad is the capital of Pakistan and the tenth largest city in the country. Located within the Islamabad Capital Territory , the population of the city has grown from 100,000 in 1951 to 1.7 million in 2011...

 experienced the record breaking 620 millimetres (24.4 in) of rainfall, which was the 24 hours heaviest rainfall in Islamabad and at any locality in Pakistan

Pakistan

Pakistan , officially the Islamic Republic of Pakistan is a sovereign state in South Asia. It has a coastline along the Arabian Sea and the Gulf of Oman in the south and is bordered by Afghanistan and Iran in the west, India in the east and China in the far northeast. In the north, Tajikistan...

 during the past 100 years. Continuous downpour

Rain

Rain is liquid precipitation, as opposed to non-liquid kinds of precipitation such as snow, hail and sleet. Rain requires the presence of a thick layer of the atmosphere to have temperatures above the melting point of water near and above the Earth's surface...

 lasted for about 10 hours from 0600-1600 PST

Pakistan Standard Time

Pakistan Time is the time zone for Pakistan. It is 5 hours ahead of GMT/UTC .The only tz database zone is Asia/Karachi.-History:The current Pakistan time was set up at midnight between 29 September and 30 1951...

 in Islamabad, caused the worst ever Flash flood

Flash flood

A flash flood is a rapid flooding of geomorphic 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...

 in the local stream called “Nulla Lai” and its tributaries, which swept away low lying areas of the twin cities. The neighbor city, Rawalpindi

Rawalpindi

Rawalpindi , locally known as Pindi, is a city in the Pothohar region of Pakistan near Pakistan's capital city of Islamabad, in the province of Punjab. Rawalpindi is the fourth largest city in Pakistan after Karachi, Lahore and Faisalabad...

 experienced 335 millimetres (13.2 in) of rain on the same day.

Causes

The cloud burst was the result of the sequel of vigorously developed cloud due to the combined effect of well marked westerly trough

Western Disturbance

Western Disturbance is the term used in India, Pakistan, Bangladesh and Nepal to describe an extratropical storm originating in the Mediterranean, that brings sudden winter rain and snow to the northwestern parts of the Indian subcontinent. This is a non-monsoonal precipitation pattern driven by...

 (Westerly wave), passing over 500hpa

HPA

-Organizations:*Halifax Port Authority, a port authority in Canada*Hamburg Port Authority, the port authority for the Port of Hamburg, Germany*Health Protection Agency, a health organization in the United Kingdom...

 with enough supply of moisture from southwest monsoon.

A surface low pressure formed over Hazara and Malakand division between 34-37ºN and 70-75ºE with central pressure less than 996 hpa. There was a gradually accentuating upper air westerly trough at 500 hpa between 40-50ºN and 60-70ºE and there were strong monsoon incursions from the Arabian Sea and the Bay of Bengal while the southwesterly monsoon current from the Arabian Sea showed strong convergence over Islamabad and Hazara and Malakand

Malakand Division

Malakand Division was an administrative division of the North West Frontier Province of Pakistan, until the reforms of 2000 abolished the third tier of government....

 Divisions and the presence of a strong southeasterly monsoon current from along the foothills of the Himalayas

Himalayas

The Himalaya Range or Himalaya Mountains Sanskrit: Devanagari: हिमालय, literally "abode of snow"), usually called the Himalayas or Himalaya for short, is a mountain range in Asia, separating the Indian subcontinent from the Tibetan Plateau...

 caused the cloudburst

Cloudburst

A cloudburst is an extreme amount of precipitation, sometimes with hail and thunder, which normally lasts no longer than a few minutes but is capable of creating flood conditions.-Etymology:There are similar names for such events in other languages...

 over the city of Islamabad.

Rainfall recorded by Pakistan Meteorological Department

Pakistan Meteorological Department

The Pakistan Meteorological Department, also known as Pak Met Office, is a Government of Pakistan organization which works under the Ministry of Defence...

 in different locations of Islamabad and Rawalpindi is detailed below.

Name of Station	Location	0500-0800 PST	0800-1100 PST	1100-1400 PST	1400-1700 PST	Total Rainfall from 0500-1700 PST
PMD Headquarters Pakistan Meteorological Department The Pakistan Meteorological Department, also known as Pak Met Office, is a Government of Pakistan organization which works under the Ministry of Defence...	Islamabad	42 millimetres (1.7 in)	132 millimetres (5.2 in)	400 millimetres (15.7 in)	46 millimetres (1.8 in)	620 millimetres (24.4 in)
Daman-e-Koh Daman-e-Koh Daman-e-Koh, about 3000ft from sea level and almost 1000ft higher than City of Islamabad, is a viewing point and hill top modern garden, popular among the residents as well as the visitors to this capital town of the nation....	Islamabad	103 millimetres (4.1 in)	Did not measure	Did not measure	314 millimetres (12.4 in)	417 millimetres (16.4 in)
Airport Benazir Bhutto International Airport Benazir Bhutto International Airport بینظیر بھٹّو بین الاقوامی ہوائی اڈہ is the third-largest airport in Pakistan, serving the capital Islamabad and its twin city Rawalpindi in the province of Punjab...	Rawalpindi	Traces	6 millimetre (0.236220472440945 in)	65 millimetres (2.6 in)	99 millimetres (3.9 in)	170 millimetres (6.7 in)
Shamsabad Rawalpindi Rawalpindi , locally known as Pindi, is a city in the Pothohar region of Pakistan near Pakistan's capital city of Islamabad, in the province of Punjab. Rawalpindi is the fourth largest city in Pakistan after Karachi, Lahore and Faisalabad...	Rawalpindi	4 millimetre (0.15748031496063 in)	83 millimetres (3.3 in)	200 millimetres (7.9 in)	48 millimetres (1.9 in)	335 millimetres (13.2 in)

Aftermath

Pakistan Meteorological Department issued heavy rainfall forecast in its Weather Broadcast Bulletin a day earlier and Flash flood Warning was issued almost 4-5 hours in advance. Due to the continuous heavy downpour the "Nullah Lai" and its tributaries over flooded and inundated the nearby houses, bridges and roads.
According to the official figures, at least 10 people died, 800 houses were destroyed and 1069 houses were partially damaged in Islamabad. Over all 61 people died of the catastrophe.