Rivers are inherently dangerous places to play, especially in the springtime when flows are high, swift and cold, but King County public safety officials and emergency responders are on extra alert for spring and summer of 2011.

An unusually heavy amount of mountain snow is melting into King County rivers this year and a tumultuous winter flood season has changed river channels and reoriented logs. And that is a recipe for river recreation tragedy, according to the King County Sheriff’s Office, Public Health, Seattle & King County, and the King County Department of Natural Resources and Parks.

“King County rivers are running fast and cold, and are always extremely dangerous this time of year,” said King County Sheriff Sue Rahr. “But 2011 could bring even higher risks. We want to get the word out ahead before the next hot weather forecast that people should stay out of the rivers at this time.”

Officials say the winter of 2010-11 has reshaped King County river channels, created new undercut banks and moved and reoriented large wood and sediment. The Cedar River was at flood stage for 12 consecutive days in January, and virtually every river system in the county experienced major flooding.

A statement by officials at the King County Department of Natural Resources said: “People should not swim in rivers, and at the very least should exercise great caution and wear a life vest when navigating or doing recreational activities on rivers.”

The snowpack in some Cascade Range river basins is roughly 200 percent of normal, which may mean higher than normal river flows well into the summer recreational season.

On average, there are 23 drowning deaths annually in King County, with 60 percent occurring in open water, including rivers, lakes and the Puget Sound.