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Natural Resources and Parks
Public Affairs

As summertime nears, King County urges caution around cold rivers, lakes, Sound


Memorial Day weekend is the unofficial start of summer, and King County officials urge everyone to be careful when heading out for fun on the water this season.


After a cold, wet winter and spring left an above-normal snowpack across the central Cascade Range, rivers across King County will likely be running swift with cold snowmelt for weeks to come. Lakes and Puget Sound aren’t much warmer options for a swim: Cold-water shock can set in after a matter of minutes in any body of water.

“I urge everyone to use caution when going into the water,” said King County Sheriff Mitzi Johanknecht. “Although the air temperatures may be warm, the waters in our region are still very cold this time of year.  I encourage you to understand the effects of cold water and be properly equipped for it.”

“Rivers can change dramatically from year to year, with trees, rocks and other potential hazards being present this year where there were no such apparent hazards last year,” said Christie True, Director of the King County Department of Natural Resources and Parks.

"Area rivers are running high, fast and cold. Local pools and life-guarded beaches are much safer places to go for a swim – particularly early in the season when a river’s water can sap even a strong swimmer’s energy in just minutes,” said Dr. Jeff Duchin, Health Officer for Public Health – Seattle & King County. “If you are on a river for other recreational activities, please use caution and wear a PFD on the water.”

A King County study of recreational river use along the Cedar River in 2011 confirmed the widely held notion that summer recreation is largely determined by warmer temperatures.
When temperatures are in the 70s, there are likely to be floaters on the river. When temperatures reach 80 or higher, floating, swimming and other recreational river use along rivers increases dramatically.

While most of those hot days occur in July and August, it is not unprecedented to have 80 degree weather in May and June – and those early months carry the most concern for river managers and emergency responders.

Flows are typically colder in late spring and early summer than later in the recreational use season, increasing the potential for cold-water shock in unprepared river users.

Higher flows in spring and summer increase velocities and decrease a river user’s reaction time to dangerous situations – including potential concealed hazards such as rocks and logs.

Seasonal flooding might have shifted rocks and logs, creating potential hazards this year where there were none last year.

King County, Public Health – Seattle & King County, and the King County Sheriff’s Office encourage kayakers, boaters, rafters, swimmers and other river users to check conditions and scout rivers thoroughly for hazards before entering the water. 

For details about river safety, visit For more information on water safety and drowning prevention, visit the King County Water Safety website,