The Attabad Lake in the Hunza valley of Gilgit Baltistan has started overflowing with the lake's water entering the spillway on Saturday morning.
The water pressure is said to be low, but fears are that that artificial lake could burst in the next 12 hours resulting in massive flash floods in the region.
"The next 12 hours could be crucial as the water flow would reach its maximum intensity, The Nation quoted an official of the National Disaster Management Authority (NDMA), as saying.
The lake near village Attabad was created due to a massive landslide on in January, which blocked the Hunza river. It is located 109 kilometers northeast of Gilgit city and 19 kilometres east of Hunza city.
The strategically important Karakoram Highway is also under threat in case the lake bursts.
NDMA chairman General Nadeem Ahmad said that the initial spill of water through the spillway would not be more than 300 cusecs.
Ahmad said rescue workers are prepared to confront any untoward situation.
Meanwhile, helicopters have been pressed into service to keep a close watch on the situation and prevent any human loss.
Authorities have already moved hundreds of people to safer places.