And as thousands of cars take detours, state troopers have noticed a spike in accidents along alternate routes.
The biggest hotspot for accidents has been Columbia Drive and the cable bridge. Just this afternoon, state troopers responded to four accidents.
We're told there's also been several accidents at the 240 roundabouts.
"When you get into the area around the blue bridge, you just need to slow down, be cautious, be aware that there's going to be heavy traffic and that there's going to be people that are uninformed about the closure and they should expect the unexpected, really," said Washington State Patrol Lieutenant Mike Saunders.
The northbound lands of 395 won't re-open until 5:30 Monday morning.