Snow cover in Northern Pakistan - the vital water resource

Snow and ice in northern areas of Pakistan are the most important source of water in the country. It is highly variable and mobile resource. Not only it is a commodity which is directly used by man but it is often the mainspring for extensive economic development.
Snow prevails or disappears in response to variation of heat flow within the earth-atmosphere.
Its contributions to biological life, recreation, agriculture, domestic and industrial water supply, and even to our less-tangible aesthetic needs are tremendous.
Northern Pakistan saw its heaviest snowfall in 30 years, the worst of it coming during the first two weeks of February. The heavy snow devastated the countries in the region including Pakistan, Afghanistan, and India. Pakistan Space and Upper Atmosphere Research Commission (SUPARCO) monitored the situation through satellite images as shown in imagel below. Only in Abbottabad district the area of snow is calculated to be 673 Sq Km.
Snow melt runoff is the most common type of flooding. These floods generally occur in summer. Heavy snowmelt runoff results from the rapid melting of snow under the combined effect of sunlight, winds, rainfall and heat waves in the region.
If there is an above-average snowfall then the potential for high volume of runoff ad subsequent flooding increases. Since the climate factors influencing the rate of snowmelt are often widespread, snowmelt runoff flooding conditions can exist over vast areas.
Temporal knowledge of the onset of snowmelt and snow water equivalent values are important variables in the prediction of flooding and water resources applications such as reservoir management and agricultural activities.
Heat wave in the country during last two weeks of June 2005 and snowmelt over Himalayan Mountains have caused flood in the River Swat and Kabul as shown in the Image2. The worst affected areas were Noshehra, Charsada and Peshawar districts of NWFP which remained flooded for almost two months.
The closed polygon in white colour shows the flooded area measurement about 100 Sq Km Satellite images of MODIS (USA) have been acquired and processed by SUPARCO using ER Mapper software.
To avoid flooding in river Kabul the proposed Munda Dam on River Swat will help in reducing the risk of flooding, besides providing water and power.
It is worth mentioning that this year the extent of snowfall has been found to be less as compared to previous year, therefore the amount of water in the rivers due to snowmelt would also be less.-Space and Atmospheric Science Division, SUPARCO