SACRAMENTO, Calif. (AP) -- California rivers fed by this winter's massive Sierra Nevada snowpack have been turned into deadly torrents, drawing warnings from public safety officials ahead of the Memorial Day weekend's traditional start of outdoor summer recreation.
At least seven people, including two children, have died or gone missing this spring in the grasp of powerful rivers plunging down from California's towering mountain range, and there have been numerous rescues.
"This year we're seeing higher water, faster water and colder water," said Capt. Justin Sylvia, a fire spokesperson in Sacramento, which is crossed by the American River.
Sacramento has already had 20 water rescues this year, nearly as many as all of 2022, Sylvia said Tuesday as crews practiced swift-water rescues on the lower American River near its confluence with the Sacramento River.
Memorial Day weekend is typically one of the busiest, if not the busiest, times of the year, and "floating down the American River is like a quintessential Sacramento activity," said Ken Casparis, spokesperson for Sacramento County regional parks.
"Probably thousands of people use the river for floating or swimming or rafting, what have you, and this weekend conditions are shaping up to be pretty dangerous, so we have been urging people to stay off the river," he said.
Even just wading along the shore is being discouraged, said Casparis, who was hoping for chilly weather to discourage river use. Forecasters predicted mild weather in the interior of Northern California except for chances of thunderstorms in the mountains.
With Californians expected to flock to the outdoors, the Governor's Office of Emergency Services on Thursday issued a broad caution about conditions they might encounter, including fast-moving water, following months of severe weather.
An extraordinary series of storms this past winter buried the Sierra range in deep snow that is now melting, swelling Central Valley rivers that just months ago were running low because of years of extreme drought.
Reservoirs that store water and provide flood control must release high flows into rivers to maintain room for incoming runoff. That, in turn, changes rivers. Sandbars and ledges may become steep drop-offs and lead to an unexpected plunge into cold water.
"It can really give a shock to the body," said Daniel Bowers, Sacramento city's director of emergency management. Experts say muscle control can be lost in minutes.
The recent tragedies include an 8-year-old girl and her 4-year-old brother, who were swept away by the Kings River on Sunday. The girl's body was found that afternoon and the boy's body was found nearly 2 miles (3.2 kilometers) downstream on Monday, the Fresno County Sheriff's Office said.
The fatal accident occurred even though both the Kings and San Joaquin Rivers have been ordered closed to recreational users since March 14.
In the Sierra northeast of Sacramento, a man was swept away by the American River on April 29, two days after Placer County authorities first issued warnings. His body was found Friday in a lake miles away. Another man who vanished in the river on Mother's Day remains missing.
Placer County's messaging about the risk is blunt. "If the public doesn't listen to our warnings this year, people are going to die, more people than we've seen over the last few years," sheriff's Sgt. Kevin Griffiths says in a public service announcement video.
The American River has not been closed to recreation in Sacramento but Bowers, the emergency management official, urged all river users to wear life jackets, even if they're using another flotation device.
American River Raft Rentals of suburban Rancho Cordova has temporarily suspended its operations on the lower segment of the river because the rate of flow is too high, co-owner Kent Hansen said Thursday.
"We definitely understand that this is part of the business and that's why we would never put profits over safety," Hansen said. "We're hoping that all of our guests will choose a safe time to go soon when water flows get back a normal, raftable flow."
Sylvia, the fire captain, emphasized that people should immediately call 911 if someone gets in trouble in the water.
"If you have a rope or if you have a life jacket that you can throw to them, do that, but do not go in the water after them because you will become a second victim," he said.
In Yosemite National Park, waterfalls have been thundering with runoff bound for the Merced River. The park has advised visitors to keep their distance from all waterways and stay off slick rocks.
"We shouldn't have to say it, but do not try to wade, swim, or float on any rivers or creeks," the park said via Facebook.
With summer approaching, the Kern County Sheriff's Office on Friday planned to carry out a ritual intended to warn people about the southern Sierra's notorious Kern River, which country legend Merle Haggard called "a mean piece of water" in his song "Kern River."
A sign at the mouth of the Kern River Canyon, which tallies the number of lives lost in the river since 1968, is updated each spring to add deaths that occurred over the previous 12 months. This year, the total was to be raised from 317 to 325.