King County crews Monday morning installed the first of 27 blue-and-white evacuation signs that will help lead evacuees to safety in the event of a major Green River flood.

The county is installing the signs on 11 roads in unincorporated areas, including the sign posted Monday on Orillia Road near Kent.

Because the Green River Valley is mostly within a city, there are few of the county signs in the lower Valley. Each city will have its own evacuation signs posted.

Also Monday, the county released a map showing the combined evacuation routes for the four Green River Valley cities - Kent, Renton, Auburn and Tukwila – as well as King County

The map is available online at www.kingcounty.gov/transportation/flood.

The county and Valley cities have worked together for several months to identify evacuation routes least prone to flooding that will provide the quickest routes to high ground.

“The whole purpose is to get you away from the flood and to high ground,” said Linda Dougherty, manager of the county’s Road Services Division.

Some of the evacuation routes, especially in outlying rural areas, could eventually flood and have to be closed. However, the routes will have served their purpose because an evacuation order would have come hours before.

Dougherty encouraged residents and businesses to familiarize themselves with a number of different routes to safety in case one route becomes blocked with traffic or water.

Police agencies also will have officers stationed on the roads in the event of a major evacuation to help direct traffic.

“We really want to reduce the panic,” Dougherty said.

Local and regional governments are coordinating emergency plans to protect public safety in the event of a major flood of the Green River. Howard Hanson Dam, which controls the river’s flow, is leaking and its operator, the U.S. Army Corps of Engineers, has warned it may have to release enough water to protect the dam that could cause flooding downriver.

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