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Thurston County, Washington

The content on the Thurston County website is currently provided in English. We are providing the “Translation” for approximately 10 languages. The goal of the translation is to provide visitors with limited English proficiency to access information on the website in other languages. The translations do not translate all types of documents, and it may not give you an exact translation all the time. The translations are made through an automated process, which may not result in accurate or precise translations, particularly of technical and legal terminology.

Emergency Management

Due to its large drainage area, the Chehalis River tends to rise and fall slowly over a long period of time. The most predictable scenario for the Chehalis occurs when rains fall over all of southwestern Washington and all regional rivers and streams rise.

However, the Chehalis can also experience flooding when there is little or no rain in Thurston or Grays Harbor counties, but heavy rain in Lewis and Pacific counties. This causes flooding to occur later than normal.

A third scenario occurs when heavy rain falls in Grays Harbor County, but not in Thurston or Lewis counties. Feeder streams can fill the Chehalis and cause water to "back up" into Thurston County.

Due to these varying scenarios, we urge floodplain residents to keep an eye on the river and to continue to monitor local media reports even if the rain has stopped and all other local rivers have receded. Minor flooding (low-lying roads and pasturelands) occurs at a gauge height of about 139.53 feet at the gauge near Grand Mound. Moderate flooding (individual residences are threatened) occurs at about 142.53 feet, and major flooding (widespread threat to communities and major thoroughfares) at about 144.03 feet.

View the river gauge for the Chehalis River at Centralia.

View the river gauge for the Chehalis River near Grand Mound.

View the river gauge for the Chehalis River near Doty.