Massive glacier broke off; An avalanche of ice and rock rushed down the river PHOTO/VIDEO

Rescuers continued searching for survivors on Thursday across Nepal’s debris-covered valleys and hillsides, while more than 1,000 people were reported missing.

It remains unclear what caused the glacier collapse. Nepalese officials initially pointed to an earthquake in the region as a possible cause, but the U.S. Geological Survey (USGS) later said the reported tremor was actually seismic energy generated by the collapse of glacial rock and ice, followed by a debris flow.

Satellite imagery shows that a large section of the glacier near the summit of Langtang Lirung broke away compared with images taken just days earlier.

As for the glacier’s size, it was approximately 1.4 kilometres high and one kilometre wide. For comparison, the Statue of Liberty is 93 metres tall, while the Burj Khalifa stands at 828 metres.

An avalanche of ice and rock swept down the Lhende Khola River, which runs along the mountainous border between Nepal and Tibet.

The landslide struck Gyirong Port in Tibet and Nepal, triggering flash floods that swept away entire roads and power facilities and inundated villages.

The International Centre for Integrated Mountain Development (ICIMOD) said on Wednesday that the flash flood generated a powerful surge of water, sediment and boulders through the Bhote Koshi and Trishuli river systems. It added that water levels in the river in the downstream Galchi area reportedly rose by as much as nine metres within 30 minutes. 

“Climate change is creating conditions that can destabilize rock and ice in high mountains,” said Simon Cox, chief scientist of the Mountains to Sea programme at Earth Sciences New Zealand.

Warming can reduce the support provided by ice on steep slopes, increase the amount of meltwater, and alter patterns of freezing, thawing and rainfall. These changes can weaken mountain slopes and make large collapses more likely in some areas, Cox added.

Nepal and China warned on Thursday of new flood risks in the Himalayas, as two lakes that had formed on either side of their border threatened to overflow in a region still reeling from this week’s catastrophic floods.