The incident in Dosquebradas, close to the city of Pereira, followed heavy rains in the surrounding coffee-growing province.
“Our updated report indicates that 35 people were injured, 14 lost their lives and one remains missing,” the UNGRD disaster agency said on Twitter of the early morning landslide in the La Esneda neighborhood. Rescue efforts were ongoing, it added.
Authorities evacuated dozens of nearby homes as the Otun river overflowed.
“A very loud noise scared us. We went out and saw a piece of the mountain on top of the houses,” taxi driver Dubernei Hernandez, 42, told Agence France-Presse. “I went to that place and it was a disaster, with people trapped.”
Mr Hernandez said he helped dig up two bodies and a survivor. He said at least five homes were buried by the mud.
The disaster agency published a photograph showing a gap in the lush green vegetation as a result of the landslide.
Rescue teams said they feared new landslides could result in the nearby Otun river being dammed, which would worsen the disaster.
Several families living close to the river were evacuated due to the risk of flooding.
“We are currently managing the entire evacuation perimeter because we still detect soil instability,” Mr Alvaro Arias, government secretary in Risaralda, told Blu Radio.
Landslides are common in Colombia due to the mountainous terrain, frequent heavy rains and poor or informal construction of houses.