UPDATE: The southbound lanes were reopened to traffic early this morning, Sunday, July 11.
Original Post: Glenn Highway travelers: beginning Friday, July 9 at 2 p.m., through Sunday, July 11, the southbound Glenn Highway will be CLOSED at the Mirror Lake exit. Southbound traffic will be reduced to one lane and detoured around the closure via the on and off-ramps at the Mirror Lake exit. Speed limits will be reduced to 35 MPH on the ramps. Please plan for extra time if you are traveling through the area. #GlennHighway
Original source can be found here.