Massive waterfalls in Yosemite National Park and rivers raging in mountains throughout the western United States are thundering with greater force than they have for years -- and proving deadly as warm weather melts the deepest mountain snowpack in recent memory.
Record snowfall on towering Western peaks this winter virtually eliminated California's five-year drought and it is now melting rapidly.
But it has contributed to at least 14 river deaths and prompted officials to close sections of rivers popular with swimmers, rafters and fishing enthusiasts.
In Utah and Wyoming, some rivers gorged by heavy winter snowfall have overflown their banks and rivers in Utah are expected to remain dangerously swollen with icy mountain runoff for several more weeks.
The sheer beauty of the rivers is their draw -- and represents a big danger to people who decide to risk selfies near the water or beat the heat by swimming or rafting with little awareness of the risks posed by the raging water.
This year's velocity and force of the Merced River that runs through Yosemite Valley is similar to a runaway freight train, said Moose Mutlow of the Yosemite Swift Water Rescue Team.
"You step out in front of it, it's going to take you," he said. "You're not going to stop that, and that's what people need to get their heads around."
Heavy storms this winter covered the central Sierra Nevada mountains with snow that remains at twice its normal level for this time of year.
While officials celebrated an end to drought in much of California, the snowmelt is so dangerous that park rangers fear its impact on the crowded park that drew a record five million people last year, when four people drowned.
So far this year, one 50-year-old man is believed to have drowned at Yosemite after falling into the Merced River from a winding trail. His body has not been found.
One of Yosemite's deadliest days was in 2011, when three young church group visitors were swept to their deaths over the 317-foot (97-meter) Vernal Fall.
Elsewhere in California, there have been at least 11 drownings since the snowpack started melting in May.
At the San Joaquin River near Fresno, 18-year-old Neng Thao drowned last month swimming in the river during a picnic with his family days before he was set to graduate as the valedictorian of his high school.
And six people have died in the rugged Tule River south of Yosemite. Some drowned, but others suffered injuries suggesting their bodies were beaten to death by the river water slamming them against the riverbed.
"The force of that water pounds people into rocks and sends them over waterfalls," said Eric LaPrice, a U.S. Forest Service district ranger at the Giant Sequoia National Monument in central California.
At the Kern River in central California, officials last month updated a sign warning that that 280 people have died in it since 1968. The sign is already outdated, with four more drownings since then.
And in northern Utah, a 4-year-old girl playing at the side of the Provo River fell from a boulder into the water last month. Her mother and a man who was nearby jumped in to try to save the girl. All three drowned, illustrating how quickly one tragedy can multiply.
"As little as six inches of water can actually sweep an adult away at the rate of speed that the water is traveling," said Chris Crowley, emergency manager for the county where Park City is located.
In Reno, Nevada, rising temperatures that have accelerated snowpack melting prompted officials to erect a sign next to the Truckee River warning people to stay away from it.
In Idaho, snowpack at double normal levels have prompted warnings from officials that densely populated areas near the Boise River could flood.
And in Wyoming, officials have placed sandbags and flood barriers to protect homes and public infrastructure from rivers and streams swollen with the snowmelt.
On his first trip to Yosemite, cartoonist Andy Runton, 42, steered clear of the turbulent Merced River.
He took a selfie at a safe distance from a grassy meadow with Yosemite Falls far behind him. Within a few hours of entering the park, Runton said the sweeping vistas and raging waterfalls had left a lifelong impression.
"You can see the power of the water," Runton said. "You can feel it. Nature doesn't slow down."
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Golden reported from Salt Lake City, Utah. Associated Press writers Scott Sonner in Reno, Nevada, and Bob Moen in Cheyenne, Wyoming, contributed to this report.
