The flooding disconnected road access between Hunza and Gilgit-Baltistan, leaving thousands of people, including tourists, stranded on both sides.
The outburst of the ice-dammed lake formed by the surging Shisper glacier also submerged four houses, agricultural land, trees, water supply channels, and two hydropower projects.
The flooding in Hassanabad nullah as a result of the outburst caused panic in the valley and disconnected road access between central and upper Hunza, leaving thousands of passengers, including tourists, stranded on both sides.
The Gilgit-Baltistan tourist police confirmed the development, adding that traffic had been diverted to an alternate route on the Sas Valley Road.
Prime Minister Shahbaz takes notice
Prime Minister Shahbaz Sharif also took notice of the GLOF and directed the concerned authorities to immediately enable the required emergency measures to cope with the situation in Gilgit-Baltistan.
The directives were issued after damage was caused by the melting of Shisper glacier, releasing a flood of water into the downstream lake which inundated the surrounding areas.
The prime minister directed authorities to shift affected families and their movable articles to safe areas and mobilise supplies of food, medicines and other emergency equipment to the affected area.
According to the authorities, water discharge from the lake started on Friday.
The Shisper glacier started to surge in May 2018, blocking water flow from a stream originating in the nearby Muchuhur glacier, which normally falls into Hunza River in Hassanabad, thus forming an artificial lake. The water in the dammed lake accumulates in winter and discharges in summer.
District administration said 8,000 cusecs of water started to discharge on Saturday from the lalce, which is over one kilometre long and as wide, and 300 feet deep.
GB Home Secretary Iqbal Hussain Khan said an alternative route for small vehicles was being regulated through Sheyar Murtazabad to Ganish. However, heavy vehicles could not go ahead of Murtazabad at present and an alternative route was being identified.
Besides, hotel associations had also been engaged to help stranded tourists, he said, adding that the administration was also regulating the supply of fuel at petrol stations and only 30 litres of fuel had been allowed to tourists only.