Islamabad is capital of Pakistan located over the foothills of Himalayas comprising steep slopes which generate high speed rainfall runoff.Heavy monsoon downpours exceeding 200mm per days during summer is the common feature of the terrain.During summer season (June-September) monsoon low pressure systems locally known as depressions form over the Bay of Bengal and they travel westward along the southern slopes of the Himalayas.Through Kashmir they enter Pakistan which is the western limit of the Asian Summer Monsoon.Due to inverted V shaped topography, rainfall intensity is generally very high as compared to rest of the areas under the influence of monsoon.Climate change has visible impacts on the increased frequency and intensity of rainfall since 1990s.On 23rd July 2001,cloudburst event produced 620mm rain during 10 hours and Pakistani capital and its neighbouring city of Rawalpindi both were heavily flooded despite the steep slopes of terrain.It took 235 human lives,3290 buffaloes and destroyed 337 houses.Damages to public sector infrastructure were estimated to the tune of $760 million.A main stream called Lei Nullah runs north to south from Islamabad to Rawalpindi discharging huge volume of water.Its basin is spread over an area of 700 km2 and several minor streams converge into the main stream.The heavy downpour event of 2001 was an extraordinary one which urged the planners to develop an effective early warning system which could save huge losses to property and human as well as animal lives.Over the basin,there are 2 river gauges and 10 automatic rain gauges passing rainfall amount at 10 minutes interval by telemetry to the control room where data processing system is installed.On the basis of analysis,alerts and warnings are generated which are then conveyed to the public through 8 acoustic siren warning posts located in the endangered population living along the Nullah Lei.The warning criteria is based on both progressive totals of rainfall in the basin and the level of river gauges at representative locations.There are four stages of the warning system i.e.pre-alert,alert,siren and evacuation.With the help of local administration,at critical levels,sometimes forced evacuation is exercised.This is the best example of public service and coordination of meteorological service and public safety sector in the region.