SEATTLE - WSDOT officials announced that the Alaskan Way Viaduct would reopen for the Monday morning commute, around four days earlier than anticipated.

But by 6:30 p.m. Sunday, both directions had reopened to traffic.

"After 10 days of around-the-clock tunneling, Bertha’s biggest hurdle is now behind her. That hurdle – the Alaskan Way Viaduct she was built to replace – will reopen for the Monday morning commute, bringing an early end to the much-anticipated #99closurE," WSDOT said in a released statement.

WSDOT structural engineers completed a thorough inspection of the viaduct on Sunday and confirmed that the ground and the viaduct has been stable during the past ten days of drilling by the State Route 99 tunnel boring machine Bertha. As of Sunday morning, Bertha had successfully drilled through 312 of 385 feet, about 75% of the way through the tunnel.

Earlier Sunday afternoon, WSDOT spokesman and program administrator for the Alaskan Way Viaduct Todd Trepanier said the viaduct would open between 4 p.m. Sunday and 5 a.m. Monday, before the peak Monday morning commute.

WSDOT temporarily closed SR 99 through downtown Seattle on April 29 so crews could closely monitor the viaduct while Bertha tunneled below. The project's contractor Seattle Tunnel Partners had originally planned to keep SR 99 closed until after Bertha had completely cleared the viaduct, and estimated it would take around two weeks.

With the ground stable and the most challenging stretch of Bertha's drilling behind her, WSDOT made the call to reopen both directions of SR 99 on the viaduct.