Residents have left eight homes in the 29-home hilltop subdivision called Lakeside Heights, and 10 other homes face evacuation, ABC News reported Monday.
A sudden rise in underground water is playing a role in the area's destruction, officials say, but they have been unable to identify an exact cause.
What began as cracks in the earth in March have widened into large holes, residents say, and a driveway attached to a home has sunk 10 feet below the level of the house.
Officials repaired broken water pipes last week but are not able to identify why water continues to bubble up to the surface and changes the terrain. Multiple causes are under investigation, and residents blame everything from a damaged fire hydrant to a dormant volcano, ABC said.
Mail carriers have been told to avoid the subdivision until the ground stops moving.
"We call it Landslide Heights," resident Randall Fitzgerald said. "Property values are gone. We have no equity. This (area) is in lockdown and probably will be in lockdown, maybe our entire lives."