Borrowed from a FB post:

520 Trail closure:

Beginning 11 p.m. Friday, Feb. 26, and continuing until 5 a.m. Monday, March 1, crews will close the SR 520 Trail across Lake Washington. The trail and all westbound lanes of SR 520 will be closed for the Montlake Project’s electrical contractor to dig a trench along the westbound lanes and install an electrical duct bank.

The trail closure on the west side of Lake Washington begins at East Park Drive East. On the east side, the trail closure begins about a half-mile from the eastern shore. Closure signs will be posted on the trail on both sides of the bridge.

Trail closure details

o   The SR 520 Trail alongside the lanes of the highway will be closed across Lake Washington.

o   Eastbound: the trail closure begins at East Park Drive East.

o   Westbound: the closure begins about a half-mile from the eastern shore.

The schedule is subject to change, and you can find updates on the SR 520 Construction Corner.