The floodwaters gushing down Little Cottonwood Canyon are the highest in a quarter century, according to Unified Fire Authority Chief Michael Jensen.
Flows peaked Sunday night and Monday morning, at 898 cubic feet per second (cfs) in Little Cottonwood Creek and 783 cfs in Big Cottonwood Creek, said Brian McInerney, National Weather Service hydrologist. Flood stage is 800 cfs in both creeks. The Weber River grew so heavy that the current broke the gauge, he said.
In all three streams, flows receded somewhat before rising again Monday night. Water levels were not expected to return to Monday morning's levels, but existing flooding means the water now has nowhere to go, McInerney said.
Even with the "herculean effort" by volunteers and emergency crews, "We are very concerned, still, about what is going to transpire over the coming days," Cottonwood Heights Mayor Kelvyn Cullimore said. "We have been told this could go on for several days."
A Sandy drainage crew worked around the clock Sunday night and Monday and saved the home of Taylor and Kim World from the fast-moving waters of Little Cottonwood Creek.
Although the Worlds' house in the 8900 block of Cobble Canyon Circle is just outside Sandy's east boundary, Ted Ketten's drainage crew jumped into the fray Sunday night as snowmelt raced down the channel after a day when the mercury rose toward 90 degrees.
"I'm happy Sandy City could help us out and help save our house," said a somewhat relieved Taylor World.
But the flooding isn't over and his house sits at a trouble spot. About 25 feet of his yard eroded into the swiftly moving waters and the creek threatened the house's foundation.
Fortunately, Sandy was building a retention pond at 11000 South and 1000 East, where tons and tons of large boulders had been delivered.
Ketten's crews trucked about 120 tons of the rocks to secure the banks near the Worlds' house.
"If we hadn't had those rocks on hand, that house would have been washed out," Ketten said.
Even after structures are saved from the rising floodwater, there will still be work ahead.
"What we're risking is they are going to have to backfill these foundations or risk some catastrophic losses," said Chris Dawson, a Sandy fire spokesman who helped with flood relief until 2:30 a.m. Monday, when the next shift took over.
The floodwaters are expected to wash away a private power plant in Little Cottonwood Canyon. Sheriff Jim Winder said Monday the plant probably won't survive the swollen stream.
The flood "is undermining the literal foundation of this building," the sheriff said during a hastily called news conference at the county's emergency operations center.
However, the loss of the small plant probably won't disrupt the valley's power and the flood won't lead to closure of Little Cottonwood or Big Cottonwood roads, authorities say.
"We don't want to close that canyon to recreational use in any way, shape or form," Winder said, "but this is one of the highest flow rates we have ever seen."
"This is the worst flooding since '83-84," said Doug Hill, Murray public services director.
There are about a dozen houses in Murray that have groundwater seeping into their basements, he said. Many of them are in the neighborhood near 5300 South and 500 East.
A nearby house at 166 Myrtle Ave. was swamped. Two renters there were able to grab some belongings before they left, Hill said.
At The Willows neighborhood in Murray, residents stood shin-deep in water moving sandbags to surround a home that had begun to flood when the area's normally tranquil creek ran over its banks.
"We're trying to stay on top of the trouble areas," said Kade Walton, a member of the Willows Home Owners Association board. "But we are worried about what will happen if the water gets much higher."
County officials had no estimates on how many homes, apartments and businesses had been damaged by the flood, nor a count of the sandbags that had been filled.
At Cottonwood Heights Elementary School, hundreds of volunteers filled thousands of sandbags, then loaded the heavy bundles into dump trucks for delivery to dozens of locations throughout the area.
Lt. Kris Ownby said Monday night that he anticipated volunteer crews to be filling bags until at least midnight.
"As long as they keep delivering the sand, we'll keep running this show," Ownby said as he looked over a small army of volunteers as they shoveled sand into white bags.
At LaCaille, an upscale French-style chateau and restaurant on Wasatch Boulevard, owner Lisa Runolfson watched as dozens of volunteers stacked sandbags against the rushing, rising water near her home on the east corner of the estate.
"I'm just so amazed at everyone's generosity," she said. "If this was the way the world always worked, we'd have far fewer problems."
Volunteer Bill Pedersen, of Sandy, was stacking bags at LaCaille after lending a hand at several other at-risk locations.
"This is the one that looks the worst to me," he said, noting that the sandbags were stacked seven deep in some areas along the bank and the water, which was already splashing across the top, was expected to rise overnight.
But for the moment, at least, Winder said, "nobody is in immediate crisis."
McInerney said the flooding has happened because of May's unseasonably cool, wet weather. The south faces of the Cottonwood canyons had snow, which is usually gone by mid-spring, McInerney said.
When temperatures suddenly peaked this weekend, snow was melting at three times its normal rate on the north faces of the mountains. When coupled with the unexpected snow on the south side of the mountains, it raised many rivers and creeks to above flood levels.
"The wildcard we have is a very moist air mass that may produce some thunderstorm activity," McInerney said. "We just hope it doesn't park over Little or Big Cottonwood canyons, the Provo River or Weber [River]."
Scattered rain showers are likely today, and Wednesday's expected high of 87 would cause the snowpack to melt even more.
In Lehi, crews tore out the road at 600 North and 100 West to allow more room for water as the culverts underground choked on heavy flows, said fire Battalion Chief Rick Howard. A main thoroughfare, 500 West, may be next, he said.
"The culverts just aren't big enough," he said.
County leaders and first responders are warning people to stay away from waterways. Deputies urged a film crew from Red Bull to get out of Big Cottonwood Creek when the group was spotted kayaking down the gushing rapids Monday evening, said Unified Police Department Lt. Don Hutson. The paddlers left the river unharmed.
Sheena McFarland and Jeremiah Stettler contributed to this report.
Want to volunteer?
Salt Lake County is asking for volunteers to help fill sandbags to protect homes from this flood and other expected floods as mountain runoff continues to keep Utah's creeks and rivers moving at high levels. Volunteers are asked to bring shovels, if possible, and gather at Cottonwood Heights Elementary, at 2415 E. Bengal Blvd. For more information on volunteering or for questions about flooding, call the county's 24-hour hot line at 385-468-6101.
O Salt Lake County has created a website publicizing the latest information on flooding. > www.slcoem.org.