SAN FRANCISCO (CBS SF) -- One lane of the northbound I-280 off-ramp at 6th Street in San Francisco has been closed Thursday afternoon as crews repair a sinkhole, according to CHP.

The San Francisco CHP Twitter account posted photos of the sinkhole at 3:15 p.m. Thursday, initially stating that the entire off-ramp had been shut down. The sinkhole appeared in the far left lane near the bottom of the elevated ramp coming off the freeway at 6th Street.

A short time later, CHP announced that the #1 lane of the off-ramp would remain closed for an unknown amount of time as Caltrans crews made repairs.

The #2 and #3 lanes will remain open. Traffic maps indicate that the lane closure is causing a back-up for drivers arriving in San Francisco.

Drivers should anticipate delays getting off of I-280 at that exit. CHP officials said they would provide updates accordingly.