A “tension crack” sliced a portion of Highway 154 open this week — and the road will remain closed until Caltrans repairs it, the agency said in a news release Thursday.

Construction crews found the crack over the weekend while repairing a slip-out in the highway.

Highway 154 was closed in both directions from San Antonio Creek Road to Painted Cave Road, with a soft closure allowing access to local businesses at Highway 192 in Santa Barbara at the Highway 154 and Highway 246 roundabout in Santa Ynez, Caltrans said.

Travelers will be redirected to Highway 101 and Highway 246, the agency said.

Construction will continue for 24 hours a day in two, 12-hour shifts until the work is done.

As part of its drilling operation, construction crews will install vertical dowels 40 feet deep under the roadway, Caltrans said.

Then, crews will start inserting horizontal dowels in the roadway over the weekend.

Meanwhile, equipment “inserted into the slope” will “monitor sub-surface movement,” the release said.

“Upon completion of the drilling, Caltrans will monitor pavement conditions before making any determination about re-opening the highway,” the release said. “It is not known at this time when this may occur or when Hwy. 154 will re-open.”