Families have begun burying loved ones killed in the disaster, which claimed the lives of as many as 43 children.
Bodies wrapped in white sheets lay on the concrete floor of the morgue in Mocoa as officials sought to bury them as soon as possible to avoid the spread of disease.
However only 45 or so bodies have so far been identified.
Maria Helena Benitez, a 50-year-old farming housewife, said: "My father's funeral is planned for this afternoon, but if his body becomes too fetid, we'll have to do it without the ceremony."
President Juan Manuel Santos, who made a second visit to the area on Sunday, blamed climate change for the disaster, saying Mocoa had received one-third of its usual monthly rain in just one night.
The heavy rainfall caused three rivers to burst their banks, sending water, mud and debris crashing through city streets and destroying houses as residents slept in the early hours of Saturday morning.