Homes person been evacuated aft a sinkhole opened up connected a lodging estate.
Local councillor David Hughes said it was believed a culvert had collapsed, creating a large spread astatine Nant Morlais, successful Pant, Merthyr Tydfil.
South Wales Police, South Wales Fire and Rescue Service and Merthyr Tdyfil assembly confirmed they were alerted connected Sunday morning.
Mr Hughes said residents of Nant Morlais - astir 30 homes - person been evacuated. The cul-de-sac has been closed and radical are being advised to debar the area.
More rainfall fell overnight, conscionable days aft Storm Bert caused flooding crossed Wales, on with a coal extremity landslide and sinkhole astatine Cwmtillery, Blaenau Gwent.
Merthyr Tydfil assembly said its unit were moving with agencies astatine Pant and "no further assistance oregon enactment is needed astatine this time".
"Thank you to everyone who has offered it," a spokesperson said.
They said information was the main precedence and advised radical to enactment distant from the area.