The Gilgit-Baltistan tourist police confirmed the development, adding that traffic had been diverted to an alternate route on the Sas Valley Road.
Hunza Superintendent of Police (SP) Zahoor Ahmed said the glacier had started melting on Saturday due to heat and caused a flood that damaged the bridge and rendered it unusable for traffic.
He said tourists were facing difficulties and had been provided alternate routes through Ganish and Murtazabad. He added that tourist police were also appointed at various spots to prevent any inconvenience to tourists.
The SP said that families near the nullah were shifted to safer places and the entire administration, including the police and rescue services, were on alert due to the emergency situation.
Chief Secretary Gilgit-Baltistan Mohyuddin Ahmad Wani said that the National Highway Authority (NHA) and Frontier Works Organisation assured him that the bridge would be repaired as a matter of urgency.
The Chief Secretary also directed GB Home Secretary Iqbal Hussain, Gilgit's commissioner and Deputy Commissioners of the concerned districts to take immediate steps for the restoration of the Hassanabad bridge and resolve the inconvenience caused to the passengers.
According to information from the Chief Secretary's office, the supply of provisions and fuel to the tourists was also being ensured along with rehabilitation and rations for the affected families.
It added that two power plants of Hassanabad were also swept away by the flood.
A statement issued by the district police said that control rooms were set up in Hunza and Gilgit, which could be contacted on 05813-930721-2 and 05811-930033, respectively.
Climate Change Minister Sherry Rehman warned that there were many such vulnerable areas in GB and Khyber Pakhtunkhwa. "Pakistan has the highest number of glaciers outside the polar region and many are losing mass due to high global temperatures," she pointed out.
Rehman had earlier cautioned the provincial disaster management authorities and home departments that due to an increase in regional temperatures, there was a possibility of GLOF events and flash floods in GB and KP.
Foreign Minister Bilawal Bhutto-Zardari also said the melting of glaciers was a "matter of concern". He said collective efforts at the international level were needed to tackle climate change.
"The situation arising out of lake eruption on Shishper Glacier needs to be dealt with on an urgent basis. The government must ensure that local communities are not harmed in any way and land routes remain open.
"Hopefully, the administration will ensure that ordinary people and tourists do not face difficulties," Bilawal said.
GB Environmental Protection Agency Director Shahzad Shigri said climate change had accelerated the melting of glaciers in the region and posed a serious threat to the population.
