UPDATE | March 8, 845AM
WSDOT said both directions of SR 18 were reopened near the accident scene north of Tiger Mountain around 8:30AM, but to expect another closure when tow trucks arrived.
It happened around 7AM, March 8, 2016. The usually jammed I-90/SR 18 interchange was unusually sparse with little to no traffic heading down Tiger Mountain toward I-90.
Then emergency vehicles, lights flashing, began heading westbound toward a reported accident near the Raging River bridge, about one mile west of I-90.
According to KIRO 97.3 radio, a garbage truck and another truck collided and the serious injury accident was blocking all lanes. Washington State Patrol (WSP) later tweeted that it appeared the two vehicles hit head on and a medical issue may have led to the collision.
The WSDOT closed SR 18 in both directions – westbound at I-90 and eastbound at Issaquah Hobart Road – around 7:30AM. They said to expected some of the lane closures to last one hour as they investigated the collision scene – and to expect long traffic delays.
Around 8AM tow trucks were en route to clear the accident and WSDOT had opened eastbound SR 18 to get tow trucks to the scene, but westbound lanes remained closed.
More info will be added as it becomes available.