ALAMEDA COUNTY (KRON) — A major slope failure has made Palomares Road in Niles Canyon completely impassable, according to Alameda County officials.

Palomares Road has been closed since last week due to the danger of rocks falling on motorists, pedestrians, and bicyclists.

The closure went into effect Thursday at about 2 p.m. between Palo Verde Road in the unincorporated community of Castro Valley and Niles Canyon Road in Fremont, said John Medlock Jr., deputy director of the public works agency’s maintenance and operations department.

During Monday’s powerful storm, a boulder collapsed on top of the road at mile marker 8.73.

At this time, there is no estimated time of when the road will reopen.