Drivers entering North Seattle should prepare for weekend detours and possible congestion as the Montlake Boulevard interchange of Highway 520 closes for construction.

All ramps that connect Highway 520 and Montlake Boulevard will close from 10 p.m. Friday until 5 a.m. Monday, along with Lake Washington Boulevard and Montlake Boulevard near the construction site.

Meanwhile, the Highway 99 tunnel closes in both directions from 10 p.m. Friday until 8 a.m. Sunday, for maintenance and to perform what WSDOT called “warranty” work on an electrical issue. Previously there have been a few minor leaks and crumbled pavement patches near the soggy south portal, repaired under warranty at contractor expense.

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At Montlake, crews are relocating sewer, gas and communications lines from the old 1960s-era overpass. They will be reattached to the new Montlake lid, said Steve Peer, spokesperson for the Washington State Department of Transportation.

The Montlake Bridge just north of the overpass also will be closed except for emergency vehicles this weekend. Crews there will be setting new girders within the drawspan decks, where new steel road grates are being installed. Drivers in the residential blocks nearby can travel just south of the bridge, with help from a pilot car, through the work zone.

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However, bicyclists and pedestrians will have a bridge and overpass route available this weekend.

Three North Seattle light-rail stations opened last weekend, creating more options to skip highway congestion. Approximately 1,500 free park-and-ride stalls are available at Northgate Station, as well as bus-to-rail connections.

The Mariners season is over, Husky football has a bye week and the Seahawks home game was Thursday night, reducing weekend traffic pressure. The Sounders do play in Sodo against Vancouver, at 6 p.m. Saturday.

Construction crews will close all Montlake interchange ramps at Highway 520 this weekend. (Washington State Department of Transportation)

Another big Montlake shutdown is planned the weekend of Oct. 23-24 when crews will raise the drawbridge’s steel spans while repairing lift equipment, closing off all bridge traffic. At the same time, Highway 520 contractors will demolish the old Montlake overpass, which will force a full highway closure, Peer said.

WSDOT is building a $4.65 billion replacement for the 1963 floating bridge across Lake Washington and Highway 520 lanes from Interstate 405 to Interstate 5. The current phase at Montlake is scheduled to finish in 2023. Traffic is temporarily winding along the new lid, but will return to a new Montlake overpass in late 2022.

In other closures, the West Seattle Water Taxi is out of service Saturday and Sunday to repair a damaged connection between dock floats. And Washington State Ferries continues to cancel some sailings because of crew shortages, especially in the San Juan Islands, and those leaving Seattle late at night.

Seattle city crews will resume installing the new Duwamish Longhouse pedestrian signal on Sunday, from 6:30 a.m. to 4 p.m., which will cause periodic lane closures on both directions of West Marginal Way Southwest, the prime detour route around the cracked West Seattle highrise bridge.