PORTLAND, Ore. (KOIN) – With the warmest temperatures of the year so far headed into the Pacific Northwest this weekend comes a stark reminder about water safety: Area rivers are still too cold to swim in.

According to the National Weather Service, any water temperature under 60 degrees are dangerous. And, according to the KOIN 6 Weather Team, the 6 major rivers in the area are all colder than that.

As of Thursday morning, the Willamette and Columbia are the warmest at 59 degrees and the Sandy river is the coldest at 51.

“Plunging into cold water of any temperature becomes dangerous if you aren’t prepared for what the sudden exposure can do to your body and brain,” The National Weather Service says on their website. “If you are planning to be on or near the water, arrive knowing the conditions and how to protect yourself.”

NWS officials say that cold water can drain body heat up to 4 times faster than cold air does. When someone jumps in dangerously cold water, the resulting “cold shock” can severely affect their breathing, heart rate and blood pressure.

“The sudden gasp and rapid breathing alone creates a greater risk of drowning even for confident swimmers in calm waters,” the National Weather Service said.

The KOIN 6 Weather Team says the predicted temperatures in the 90s Saturday, Sunday and Monday will also increase snowmelt from the Cascades, which will likely keep area rivers colder than that 60-degree mark for at least the next several weeks.

If you are going to recreate in area rivers on boats, personal watercraft, kayaks or paddle boards, the KOIN 6 Weather Team reminds you to wear life jackets or other personal floatation devices.