'It’s a lot more intense on the river': Wild whitewater rafting this Memorial Day weekend

Whitewater rafters looking for big waves and an adventure on the American River this Memorial Day weekend are being warned by professional guides that danger is lurking if they don't take the proper safety precautions.

"The water’s much colder than normal, it’s moving at a faster pace," Scott Armstrong, owner of All-Outdoors Whitewater Rafting in Lotus said. "If you’re going to go near the water, please, have a life jacket."

With the massive snow pack caused by a series of winter storms melting in the Sierra Nevada, the South Fork of the American River, northeast of Sacramento is running 10 feet or higher than usual.

And with the drought over the last several years, rafting guides consider it a once-in-a-decade kind of season.

"It’s like skiing on a powder day, this is what we’re looking for," Armstrong said. "It’s the ultimate in whitewater fun."

The water is cold -- roughly 48 degrees -- and rushing at a rate several times faster than previous years.

Reservoirs that store water and provide flood control must release high flows into the river to make room for incoming runoff.

That means extra safety precautions have to be taken included wetsuits, life jackets, and rafts outfitted with special equipment better suited for guides to maneuver the swift water.

The large rocks or trees that guides normally have to navigate around are now underwater, creating new challenges including large waves and big splashes.

"We have been preparing a lot," said Phillip Schoenhoff, owner of Whitewater Excitement. "All our guides have been training every day on this river at these flows. It’s a lot more intense on the river."

Schoenhoff’s business in Lotus, a small town in El Dorado County, has stepped up the minimum age from seven years to 12 years old because the water current is faster.

All rafters go through a safety seminar before getting into a raft and onto the river. Guests are also getting vetted before being allowed to participate.

"We are making sure everyone coming rafting with us is in good, physical condition," Schoenhoff said. "Swimming ability is required and they should be on the adventurous side."

But there are still dangers.

Typically, the deaths and close calls are caused by those venturing into the river on their own to swim, float or paddle. Emergency first responders are advising against that this weekend.

California rafting companies are monitoring the water flows using graphs and data supplied by the state.

Fearful first timers are encouraged to come later in the summer when water levels are expected to be lower and a tad slower.

"This is not the year to be drinking and swimming, this is not a time to go on a float," Armstrong said. "You need to be mindful. Be careful. And if you do want to experience the rivers, go with a professional."

Brooks Jarosz is a reporter for KTVU. Email him at  brooks.jarosz@fox.com and follow him on Facebook and Twitter @BrooksKTVU