UPDATE | August 27, 2015
The City of Snoqualmie stated that WSDOT has cancelled the weekend closure of SR 18 between Issaquah-Hobart Road and I-90 interchange for August 29th and 30th. The project is weather dependent and so the project has been postponed.
This weekend, August 29th – August 30th, traffic on westbound I-90 between North Bend and Issaquah, as well as the SR18/I-90 interchange, may cause headaches as large sections of SR 18 will be completely shut down for planned roadwork projects. 
The Washington State Department of Transportation (WSDOT) warns drivers who use SR 18 near Snoqualmie and Tiger Mountain, as well as Auburn, to prepare for full closures and detours from 6AM to 3PM Saturday, Aug. 29th, and 6AM to 2PM Sunday, Aug. 30th.
WSDOT maintenance crews will close both directions of SR 18 between Issaquah-Hobart Road SE and I-90 for paving, guard rail and tree removal work.
Eastbound drivers will be detoured onto Issaquah-Hobart Road SE. Drivers on Snoqualmie Parkway and I-90 who wish to go westbound on SR 18 will be detoured onto westbound I-90.
In addition, all westbound lanes of SR 18 from SE 304th Place to SE Auburn-Black Diamond Road will be closed for tree removal work. Drivers will be detoured onto SR 516 in Covington.
Plan ahead and bring your patience if your travels are impacted by these closures and detours.
Comments
I travel hwy18 regularly as I live in maple valley. There is an information board between so. 256th exit and so. 231st exit, why does this board not inform travelers of weekend closure? I learn closure info is posted on hwy 167 and I 5. Nothing posted on hwy 18 at all. Nice job wsdot
The only closure sign I have seen is on the side of 1-90 west bound before the highway 18 exit. They should have info on highway 18.