Cities across the Wasatch Front are preparing for higher stream flows and potentially more flooding in the coming days, as high temperatures jump back into the 70s and 80s this weekend and into early next week.

The National Weather Service on Thursday issued a hydrologic outlook that advises there is a "high chance of localized flooding" in some of northern Utah's mid-elevation watersheds, as streams, creeks, and rivers all over the state are expected to experience "significant rises" this weekend into early next week.

"Given record snowpack in our area mountains, these temperatures will lead to accelerated snowmelt of low- and mid-elevation basins, leading to the high flows," the agency wrote in the alert.

A 'spring heatwave'

The real warmup is expected this weekend after a "backdoor cold front" reaches parts of the state Thursday night and Friday morning. KSL meteorologist Matt Johnson explains that the cold front is helping push storms south into areas east of Utah but will mostly only send clouds into the Wasatch Front.

Temperatures won't be impacted too much either; however, since the cold front will enter the Wasatch region from the east, it's expected to produce downslope winds partially in Davis and Weber continues, the National Weather Service tweeted. The agency advises that wind gusts of 35 to 45 mph are expected, especially between 11 p.m. Thursday and 6 a.m. Friday.

The next high-pressure system begins to move over the Great Basin on Saturday, producing what Johnson calls a "spring heatwave." The current forecast calls for temperatures to jump 15 to 25 degrees above normal between Saturday and Wednesday, with highs reaching into the mid-to-upper 80s by the start of next week.

The issue is that while nearly half of the snowpack has already melted within the Southwestern Utah snowpack basin since the first week of April, the snowpack basins around the Wasatch Mountains and West Uintas have not changed much this month.

Storms over the past few weeks have kept temperatures low enough and even added additional snow, so much so that only 3% to 12% of the state's six northernmost snowpack basins have melted, as of Thursday afternoon. That means there is a lot of water left to melt into the creeks, streams and rivers that flow through the Wasatch Front, Cache and Tooele valleys, as well as the Uinta Basin.

"We've got to be a little concerned here," Johnson said.

Utah isn't alone in this issue. The weather service's other offices have already issued flood watches in parts of California, Idaho and Nevada because of similar snowpack runoff concerns. Those remain in effect through Tuesday.

"It's going to hurt a little but we've got to get (the snowpack) down. We've got to get it down some way," Johnson adds. "Right now, we're looking at an extreme high in the temperature for this weekend."

Flooding at Sugarhouse Park on Wednesday, April 26, 2023. | Scott G Winterton, Deseret News

Preparing for the higher water levels

Communities along the Wasatch Front are bracing for stronger streamflows in the coming days. For example, the Salt Lake City Department of Public Utilities said Thursday that it has sandbags staged at various locations in the city "for quick deployment" if needed.

Laura Briefer, the department's director, said the city anticipates having the capacity to "accommodate the forecasted stream flows" at the moment, but both Salt Lake City and Salt Lake County water experts will "continue monitoring and cleaning the drainage system around the clock."

Salt Lake City has already dealt with flooding this month from snowmelt that has taken place this season. A large piece of metal clogged a flood control culvert along Emigration Creek near Wasatch Hollow Park, resulting in flooding that caused 40 homes to be voluntarily evacuated on April 12.

"We continue to encourage residents to familiarize themselves with flood zones and to reach out if they see creeks backing up or grates clogged by debris," Salt Lake City Mayor Erin Mendenhall said.

Sugar House Park in Salt Lake City is one of the tools being used to help prevent flooding. It remains closed to vehicle traffic as its retention pond fills up. The pond is a catch basin designed to collect additional flows from Parleys Creek so that it doesn't flood homes and businesses in the area.

Miranda Page jumps out of the water as her friend Melinda Messner stands on a park bench that is surrounded by floodwater at Sugarhouse Park on Wednesday, April 26, 2023. | Scott G Winterton, Deseret News

Cleanup crews also spent Wednesday night and Thursday morning clearing debris in American Fork Canyon, so that the river can flow more efficiently and potentially avoid flooding. Utah Gov. Spencer Cox traveled to American Fork on Wednesday to announce a new partnership with LiveView Technologies, which will install about 20 surveillance cameras that will be used to track possible spring runoff flooding across the state.

The Central Utah Water Conservancy District also opened the floodgates of a facility by the Point of the Mountain on Tuesday to allow for 50 million gallons of water to flow into the Jordan River as a way to reduce flooding severity in the region, while also sending the water to the struggling Great Salt Lake.

Meanwhile, the strong streamflows are expected to be "cold and extremely dangerous," the National Weather Service warns. Richard Boden, the emergency manager for the Salt Lake City Fire Department, said Thursday Utahns should avoid getting near any high-moving waterways this weekend.

"The streams are flowing fast, may be deep and are very cold," he said. "Do not go in the water (and) keep your children and pets safe."