A 65ft wide sinkhole has opened up overnight in a residential cul-de-sac in St Albans.
Six homes were evacuated after the 32ft deep chasm opened in Fontmell Close at 1.20am.
A spokesman for Hertfordshire County Council said affected residents have been evacuated to a nearby sports centre and the Red Cross are at the scene.
She added: "It was reported as a small hole last week and was ironically due to be filled today."
A Herts police press officer said: "Residents have been evacuated as a precaution and all utility services (such as gas and water) are being checked and turned off. A reception centre has been set up for the residents who have been evacuated from their homes at Batchwood. There is currently no access for vehicles to the close."
52 properties in the area have no utilities. Julie Langford, who lives on the street, told Sky News all of the residents in the street have had their vehicles blocked in by the sinkhole. She added she had been warned it could take weeks - possibly months - before the road is repaired.
She added: "I can't walk to work - I have an hour's commute in the morning. The children can walk to school, but when you're a mum of four children it's not easy."
Sinkholes are cavities in the ground usually caused by water erosion.