As a reminder, Bertha was originally supposed to be surface in South Lake Union in October 2014 and the tunnel was supposed to open by the end of 2015.
Last week we found out WSDOT and Seattle Tunnel Partners were going to need to close the Alaskan Way viaduct for two weeks while Bertha dug underneath. Friday they announced that the official start date for that two-week closure will be April 29.