Crews still don't know what's blocking Bertha

SEATTLE -- It's been a few weeks, but we still don't know what is blocking Bertha's path.

A senior engineer told the Seattle Times that workers have checked the soil in six spots in front of the SR-99 tunneling machine but haven't bumped into anything yet.

Contractors will likely send workers into Bertha's flooded front end on Thursday to see if they find anything.

The 7,000 ton machine is 60 feet underground working on a new tunnel that will replace the Alaskan Way Viaduct.