As record temperatures melt northern Utah’s record snowpack, rivers and streams will be “running high, fast, cold and extremely dangerous” for the next few days, according to the National Weather Service.
On Sunday, the high temperature in Salt Lake City hit 87 degrees — a new record for April 30, and 21 degrees above normal. (The previous record for the date was 84, set in 2021.)
Another heat record was matched as of Monday afternoon, when Salt Lake City hit 87 degrees. The city last hit 87 degrees on Monday’s date (May 1) in 2007, when the record was set, according to the weather service.
Highs in the low 80s are also forecast for Tuesday and Wednesday.
Temperatures running 15 to 20 degrees above normal “will lead to accelerated snowmelt of low and mid-elevation basins,” according to the weather service, creating “a high chance of localized flooding throughout the upcoming week.”
Flood fears rise along Emigration Creek
Laura Briefer, director of Salt Lake City’s Public Utilities Department, said the forecast for Monday night, Tuesday and Wednesday shows peak flows exceeding 160 cubic feet per second along Emigration Creek.
“If we are going to see these 160-plus peaks over a sustained time the next few days,” she warned, “that’s going to challenge the system.”
In mid-April — when a clog in the flood-control system sent water spilling down the roadway near Wasatch Hollow Park — flows on the creek peaked at 155 cfs.
Briefer said city public utilities employees and Salt Lake County flood control crews are going to work closely to manage the flood control system this week.
That means directing the two detention basins on Emigration Creek — one at Rotary Glen Park and the other at Wasatch Hollow Park — to ensure there’s enough space to capture the runoff.
“That works,” she said, “to sort of shave the intensity of the peak downstream.”
Briefer said Emigration Creek does have the capacity to carry the runoff, but officials will be watching to ensure the water flows through culverts and into the pipe system without issue. Teams will also be on guard for storm-drain lids coming dislodged from peak flows.
If flooding occurs, Briefer expects it to be minor and limited to roadways.
The effectiveness of the system that controls Emigration Creek depends on avoiding debris that could cause clogs.
On Sunday, Briefer said, a wooden pallet got lodged into the stream and caused water to flow over Emigration Canyon Road above Rotary Glen Park.
“When we have flows this high,” she said, “the sensitivity of the system to things like obstructions is quite high as well.”
Briefer said the public should avoid areas around the stream and keep an eye on children and pets. She also urged residents and businesses near streams to remove any debris that may be washed into the waterway.
To report issues or concerns about the condition of Emigration Creek, call the Public Utilities Department’s 24-hour dispatch line at 801-483-6700.
Other flooding concerns
(Trent Nelson | The Salt Lake Tribune) High water levels in Salt Lake City's Sugar House Park, which serves as a detention basin for Parleys Creek flood control, on Wednesday, April 26, 2023.
• Minor flooding is also expected near the south fork of the Ogden River near Huntsville, according to the National Weather Service.
• The lower Weber River near Plain City and east Canyon Creek from about Jeremy Ranch to the East Canyon Reservoir remain under flood watch until further notice.
• Flooding temporarily closed about 30 miles of U.S. Highway 89 through Spanish Fork Canyon, from the intersection of U.S. Highway 6 near Thistle to Mount Pleasant. The Utah Department of Transportation advised Monday that Thistle Creek is expected to remain high for the next several days and additional closures may be necessary.
• A flood warning remains in effect through Friday morning along the Little Bear River near the town of Paradise, about 12 miles south of Logan. Minor flooding is expected in farmland and low-lying areas.
• The mayor of Garden City declared a state of emergency in the small town on Bear Lake just south of Idaho. He urged owners of vacation homes there to check on their properties because of minor flooding in the area.
• State Road 210 through Little Cottonwood Canyon remains closed for avalanche work. UDOT had no estimate for when it will reopen as of Monday afternoon.
• State Road 190 through Big Cottonwood Canyon was closed until 5 p.m. Monday for avalanche mitigation.
Temperatures expected to drop again
Temperatures are expected to cool Wednesday night into Thursday, according to the weather service. Highs in the low 70s are expected along the Wasatch Front on Thursday, followed by temperatures in the low to mid-60s Friday through Tuesday.
The cold front is expected to bring valley rain. There’s a 60% chance of rain on Thursday, including a chance of afternoon thunderstorms. Mountain snow is expected above 7,000-8,000 feet, although little accumulation is expected.
Temperatures will also drop in southern Utah, from nearly 90 degrees on Monday in the St. George area to the low 80s on Tuesday and Wednesday. The forecast high on Thursday is in the mid-60s, and there’s a 50% chance of rain, with thunderstorms possible.
Skies will clear Friday and temperatures in the mid-70s are expected through the weekend, a bit below normal (about 80 degrees) for this time of year.
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