SR 520 - Floating Bridge and Landings Project - Sentinel lights

What are the sentinels?

The new SR 520 floating bridge has four large towers, called “sentinels,” that mark the east and west ends of the world’s longest floating bridge. The tallest one, at the bridge’s east end, rises 123 feet above the lake’s surface. These towers not only add an architectural flair to the bridge, but also serve a critical function, allowing crews access to the bridge’s pontoon platform for maintenance.

Sentinel lighting

We illuminate the sentinels from dusk to dawn with LED lights. Teal is the standard color. Many color combinations are possible, however, which allows us to change the display color to commemorate holidays or support public events or causes of community significance.

What color are the sentinels tonight?

Right now, the sentinels are displaying their normal teal color.

A tower that is part of the state route 520 floating bridge is lit up teal blue as the bridge extends over water into the distance in the evening.

How can I request a color change?

If you are interested in changing the sentinel lights for a public event or cause, please fill out our Sentinel Lighting Change Request Form (pdf 375 kb) and submit it to Sentinel light changes are intended to recognize holidays and national and local campaigns, organizations and events of public significance. We cannot accommodate requests related to private events or political or religious events or campaigns. Details about the lighting policy and request process are listed in the request form (pdf 375 kb).

What lighting changes are coming up?

A calendar of the month of May titled sentinels schedule May 2019. The nights of May 3 to 5, 6 to 17, and 24 to 26 are shaded in various colors representing sentinel lighting reservations.


Dates: Friday, May 3, to Sunday, May 5
Color: Blue
Cause: CancerCare Day
Description: The sentinels will be lit blue to honor CancerCare's 75th anniversary. CancerCare is a national nonprofit offering support services to to cancer patients across the country. 


Dates: Monday, May 6, to Monday, May 13
Color: Orange
Cause: Fred Hutch Obliteride and Cancer Research Month
Description: The sentinels will shine orange to highlight cancer research month and to support Fred Hutch's Obliteride, a bike ride fundraiser to accelerate cancer research at Fred Hutch.


Dates: Monday, May 13, to Wednesday, May 15
Color: Turqoise
Cause: Women's Lung Health Week - American Lung Association
Description: The SR 520 bridge is partnering with the American Lung Association to support Women's Lung Health Week. Lung cancer is the number one cancer killer of women in the U.S. The American Lung Association is determined to raise awareness about this issue and help save lives.


Dates: Wednesday, May 15, to Friday, May 17
Color: Green
Cause: National Public Gardens Week - American Public Gardens Association
Description: The sentinels will be shine green to highlight National Public Gardens Week. The American Public Gardens Association represents over 600 botanical gardens and arboreta including 15 gardens in the Seattle area. National Public Gardens week was created to drive local and national exposure to the importance of gardens to community enrichment and environmental responsibility through community engagement, sustainable practices and conservation.


Dates: Friday, May 17, to Saturday, May 18
Color: Blue and green
Cause: World Neurofibromatosis Day - Children's Tumor Foundation
Description: The sentinels will shine blue and green to recognize World Neurofibromatosis (NF) Day. May is NF Awareness Month, a time to connect, understand and educate about NF, a rare genetic disorder that affects 125,000 people across the U.S. The Children's Tumor Foundation leads "Shine a Light on NF," part of a month-long awareness campaign designed to educate the community about this under-recognized genetic disorder


Dates: Friday, May 24, to Monday, May 127
Color: Red, white and blue
Cause: Memorial Day
Description: The SR 520 bridge will shine red, white and blue to honor Memorial Day 2019 and to remember and honor all who have lost their life while serving in the United States Armed Forces.