information from SDOT
The off-ramps to Harbor Island from westbound West Seattle Freeway and from southbound SR99 will be closed this coming weekend beginning Friday evening, September 9, at 7 p.m. The off-ramps will be reopened Monday morning, September 12, by 5 a.m. The closures are needed in order for the replacement of three railroad crossings at the south end of Harbor Island.
• Motorists who are not in large trucks/commercial vehicles can detour by taking the high level West Seattle Bridge, using the Delridge Way exit, then taking the right onto Chelan Ave SW, another right onto SW Spokane St, and eastbound across the Duwamish West Waterway and back onto Harbor Island.