Nepal began burying victims of a flash flood that struck the Himalayan region on Wednesday, raising the confirmed death toll to 903, while 4,247 people, including 592 foreigners, remained missing according to Nepal’s disaster agency.

The flood occurred after a glacial collapse high in the Himalayas caused a rockfall that registered as a magnitude 5.2 earthquake, sending a wave of water, ice and debris down valley rivers and overwhelming settlements in Nepal and Tibet.

Rescue operations continued on Sunday, with Nepali army troops and engineers searching a tunnel at the Trishuli 3A hydroelectric plant after inserting a pipe to reach workers believed trapped. Surendra Dowluri, a worker rescued after four days, said the water submerged the turbine floor and left six workers stuck, of whom five were rescued and one died.

Overnight rain and rising river waters on Sunday filled excavation areas with water, hampering rescue efforts, according to the Nepali army.

Brigadier General Raja Ram Basnet, the army spokesman, said rescue efforts were being intensified in hills, settlements and river areas.

Because of the large number of bodies and lack of freezing facilities, authorities began burials before completing DNA identification, which families will use later for traditional funeral rites. Relatives gathered at identification centres to view pictures of recovered bodies on LED screens, some of which they recognized.

In northern Nepal, residents expressed fear of additional flooding as water levels rose.

Scientists said satellite imagery indicated that bedrock beneath a glacier collapsed, taking part of the glacier with it, which triggered the flood.

The disaster has left thousands still unaccounted for, and emergency workers continue to monitor large lakes formed by debris that may pose further risks.