Colder, faster moving water in local rivers has claimed several lives this summer, and officials warn this may be one of the most dangerous seasons in recent history.

Bob Hemus, a river safety specialist for the Water Safety Coalition of Northwest California who has worked in Humboldt County for more than 30 years, said it is one of the worst he's seen.

”We haven't had a year like this,” he said, noting the late spring rain and high snow levels are creating the dangerous conditions.

Three of the most visited rivers in the area -- the Klamath, Salmon and Trinity -- receive water from high mountains. For example, the Trinity River in Willow Creek is fed by the Trinity Mountains. When the snow melts, water runs down the mountains and increases the water levels.

The average volume on the Trinity River over the last 47 years is 1,170 cubic feet per second. The maximum recorded before this summer was in 1998, when the number reached 3,120. Last Friday, the water discharge at the Trinity was 3,220 cubic feet per second, according to the U.S. Geological Survey. There have been similar increases on the Salmon and Klamath rivers.

”We can't tell people not to go to Willow Creek,” Hemus said. “We can just tell them to be careful.”

Recent deaths include a Hayward man who was pulled out of the Eel River on July 18 after suffering a cramp. Another man died July 6 in the Mattole while reportedly trying to learn to swim, and Humboldt State University foreign exchange student Jian Kang died on June 19 after he slipped while wading in the Trinity River and was swept downstream. His body was found 10 days later.

More than 40 percent of all recreational water drownings in 2007 occurred in natural water settings, according to the California Center for Disease Control. Locally, 25 people drowned between 2005 and 2010, according to Sandy Walsh, coordinator of the Water Safety Program at the Humboldt County Department of Health and Human Services.

Troy Nicolini, National Weather Service spokesman and chair of the Water Safety Coalition, said that it's more than just waves and currents that create a dangerous situation, it's also the water temperature.

”People may survive whatever happens if it wasn't for the temperature,” Nicolini said. “You could be Michael Phelps and you're not going to get out of it.”

He said cold water can cause temporary paralysis to a swimmer due to the bloodstream rushing to the torso, leaving one's limbs incapacitated and unable to tread water.

Nicolini said that the number of deaths is staying constant in the area, despite the amount of visitors increasing. He attributes some of that to increased efforts countywide.

”It's clear people had no idea what those hazards were,” he said. “But it's holding steady, and that gives us hope.”

The rivers are where many in Humboldt County spend their summer vacations. It's also one of the major lures of the area. Hemus said that trying to dissuade people from enjoying them would have a large impact on the businesses that rely on river-goers for income.

Officials recommend wearing lifejackets in and around the waters of Humboldt County, and there are five local locations where vests are loaned, free of charge, including the Early Bird Café in Willow Creek.

Owner Lee'Ann Brander said a lot of people aren't aware of the service.

She recalled an instance when a woman with four children, one as young as 6 months old, were at the restaurant and intended to go out on the river with no protection. She said the woman told her that she couldn't afford vests and would have gone to the river without them had the service not been available.

”It's not a good thing to see,” Brander said.

She said that the number of vests is limited due to some not being returned.

Hemus said a life vest would have given Kang a “95 percent chance of living.”

Nicolini said his family always wears vests when fishing close to the water line or clamming for mussels.

”If you have to be close to the ocean, wear a life vest,” he said.

At a glance: Reducing risks

* Learn CPR

* Never turn your back on the ocean

* When boating, carry a radio

* Alert someone of your day plans and when you will be home

* Be aware of weather conditions

* Adults should be safety role models by wearing a life vest

Source: Humboldt County Water Safety Program

Locations to borrow life jackets:

Dream Quest: 100 Country Club Drive, Willow Creek, 530-629-3564

Willow Creek Motel: 375 State Highway 96, Willow Creek, 530-629-2115

Early Bird Café: 40640 State Highway 299, Willow Creek, 530-629-4431

Tsewenaldin Inn: State Highway 96, Hoopa, 530-625-4294

Tsunami Surf & Sport in Garberville: 445 Conger No. B, Garberville, 707-923-1965