SEATTLE — 11:13 a.m. UPDATE:
The Washington State Department of Transportation says the SR 99 tunnel has fully reopened.
Thursday morning the power to the ventilation system went out, prompting a full closure and creating a traffic nightmare for those commuting through the city.
11 a.m. UPDATE: According to WSDOT, the southbound SR 99 tunnel is back open with power restored to the ventilation systems. Crews are working to reopen the northbound SR 99 tunnel momentarily.
PREVIOUS COVERAGE:
The SR 99 tunnel in Seattle was closed in both directions on Thursday morning due to a power outage.
The Washington State Department of Transportation (WSDOT) first shared the closure at 7:39 a.m.
As of 8:10 a.m., WSDOT said there was no time estimate for when power would be restored and the tunnel reopened.
According to WSDOT, the outage affects the ventilation system, so the tunnel must remain fully closed until power is restored. WSDOT confirmed that Seattle City Light was working to restore power.
A spokesperson with Seattle City Light told KIRO 7 that the cause of the power outage was downed wires in the vicinity. They say crews are working to isolate the issue and return power to the tunnel as soon as possible.
Drivers were told to seek alternate routes and plan for added travel time.
This is a developing story. KIRO 7 has a crew on the scene of the downed wires.
UPDATE: The SR 99 tunnel remains closed in Seattle due to a power outage. There is no estimate for power restoring/the tunnel reopening. Seek alternate routes and plan for added travel time. @SEACityLight @seattledot @GoodToGoWSDOT https://t.co/ASQjEqVM3U pic.twitter.com/KDOt0JMusI
— WSDOT Traffic (@wsdot_traffic) November 20, 2025
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