A SEARCH for the missing has resumed in Colombia after surging rivers sent an avalanche of floodwaters, mud and debris through a small city in the early hours of Saturday morning, killing at least 250.

Piles of rocks and wooden planks entombed homes in Mocoa.

Streets were covered in thick sand, mud and tree limbs from the rivers and rainforest that surround the city. There was little drinking water and no power, which forced authorities to suspend the search-and-rescue effort during the night.

The National Disaster Agency said the death toll was at 200, with another 200 injured, but authorities conceded it could easily go higher because many people were still unaccounted for, dozens were airlifted to hospitals in other cities and others were in critical condition.

Bodies were being placed in a temporary morgue where three teams of medical examiners were working around the clock to swiftly identify the remains.

Authorities and residents in the city tucked between mountains along Colombia’s southern border spent Saturday tending to victims, trying to find homes on streets reduced to masses of rubble and started a desperate search to locate loved ones who disappeared in the dark of night.

Eduardo Vargas, 29, was asleep with his wife and seven-month-old baby when he was awoken by the sound of neighbours banging on his door. He quickly grabbed his family and fled up a small mountain amid cries of people in panic.

Vargas and his family huddled with about two dozen other residents as rocks, trees and wooden planks ripped through below.

They waited there until daylight, when the military helped them down. When he reached the site of his home on Saturday, nothing his family left behind remained.

President Juan Manuel Santos travelled to Mocoa and declared the city a disaster zone on Saturday.

The Air Force transported 19 patients to a city farther north and said 20 more would be evacuated soon.

Medicine and surgical supplies were being sent to the city as the area’s regional hospital struggled to cope with the magnitude of the crisis.