Two houses have partially collapsed after a sinkhole measuring 10ft (3m) opened up on a Manchester street.
Four homes were evacuated on Wednesday evening after the hole appeared on Walmer Street in Abbey Hey, Gorton.
Fire crews returned hours later after the front of two of the empty properties crashed to the ground.
United Utilities said it was dealing with a collapsed sewer but was investigating all possible causes including the recent heavy rain.
The fire service was first called to Walmer Street just after 21:00 GMT on Wednesday to reports an unoccupied car had fallen down a hole in the road.
A cordon was put in place and residents evacuated as a precaution, the fire service said.
After leaving the scene four hours later, the fire service was alerted to the partial collapse of two houses at 11:00 on Thursday.
No-one was injured in either incident.
Nearby residents Maureen and Louise Kennedy spoke of their shock after the houses collapsed.
"You're just waiting for your world to crumble. It's not just the bricks and water, said Ms Kennedy.
"I've lived in there since I was three. It's the memories."
Resident Nathaniel OKeleafor said he was "terrified" when the sinkhole appeared in the street on Wednesday evening.
"This morning we are out. We are just trying to find somewhere to live," he added.
The collapse comes as rising levels on the River Mersey in Manchester came "within centimetres" of breaching flood defences following heavy rain caused by Storm Christoph.
Station Manager Andrew O'Brien, from Greater Manchester Fire and Rescue Service, praised firefighters who worked "at the height of the stormy weather".
"The safety of the public was our primary concern overnight and again today, and I'm pleased to say no-one has suffered any injuries," he said.
United Utilities said: "When it is safe for engineers to go back into the immediate area we will set up emergency drainage and water supply connections to restore services to the area and begin to assess how best to carry out repairs.
"It is not known what caused the sinkhole but this will be investigated."