The city of course hopes it never comes to this, but they are planning for a worst case scenario in which the bridge becomes so unstable it could collapse.
After studying the extensive cracking on the West Seattle High Bridge that prompted its emergency closure in late March, SDOT has installed monitoring devices to alert them of further movement. And they are preparing a plan to evacuate nearby areas and close the lower swing bridge that is now a lifeline for the neighborhood, providing a walking, biking, transit, freight and emergency vehicle connection.
“[T]here are currently no indications that we will need to put our emergency response plan into action,” SDOT wrote in a blog post describing the new plan. The plan includes three potential responses based on possible emergency circumstances:
- Immediate evacuation to be used if the daily in-person inspections indicates enough of a change to warrant the immediate evacuation of a small number of properties (details shared below), though we could have hours or days before actual bridge failure.
- One to five days notice to be used if the new remote monitoring instrumentation, which will be fully functioning in mid May, indicates enough of a change to warrant execution of evacuation plans within one to five days. If failure is anticipated, but not immediate, SFD and SPD will clearly communicate, via direct site visits and other platforms, when evacuation must occur.
- Controlled demolition to be used if the change in the condition of the high bridge indicates the need for execution of an evacuation plan followed by a controlled demolition.
Here’s what the emergency road closures would look like:
If you want to make sure you are alerted if the plan goes into effect, sign up for AlertSeattle text messages. You should also make sure Wireless Emergency Alerts (the service that sends Amber Alerts) are enabled on your phone.