Most of Utah is under a ‘hydrologic outlook’ advisory as Salt Lake City prepares to hit the early 80s early next week, according to the National Weather Service.
The advisory was issued about 1:30 p.m. Thursday afternoon, and warns of “significant rises” in waterways due to increased snowmelt. The service urged caution as cold water in rivers, creeks and streams will be running fast — so even brief periods of time in the water could lead to hypothermia.
Early next week, there is a high chance of localized flooding in some mid-elevation watersheds in northern Utah, the service said. A high pressure system moving through the state will also lead to temperatures 15-20 degrees above normal, accelerating the melt of the Utah’s record snowpack.
In Salt Lake City, forecasters expect a sunny weekend with a peak high of 83 degrees on Monday. Temperatures then cool off with a chance of showers on Thursday and a forecasted high of 70 degrees.
Salt Lake City’s Department of Public Utilities is preparing for the increased stream flows amid the higher temperatures, and anticipates the city’s systems will be able to accommodate the snowmelt. Runoff experts will also continue monitoring and cleaning the city’s drainage system “around the clock,” said Laura Briefer, director of Public Utilities, in a statement.
Emigration Creek and Red Butte Creek are the city’s main focuses right now, said Brian McInerney, a hydrologist consulting with the city on flooding. City Creek, Big Cottonwood, Mill Creek and Little Cottonwood canyons have such large snowpack that it will “take a while” before they yield meltwater, he added.
“They’re not ripe, so we’re not seeing much rise,” McInerney said “It will pick up though, but they’re just a little later. But the lower elevation watersheds like Red Butte and Emigration, we’ll start seeing those pickup quicker, but we’re still not to any flooding.”
Officials expect the highest flows to occur around late May and early June.
“What we’ve seen so far is that inability for the streams to get to rise, even though it’s hot, because they’re not isothermal, they’re not yielding meltwater,” McInerney said. “So think of a drop of water at the top [of the mountains] gets in the sun, melts, and starts trickling through the snowpack and makes it about — and I measured this two days ago — 35 centimeters down. And then it refreezes because the pack is cold so that water doesn’t make it into the soil or the streams.”
Controlled releases from Mountain Dell and Little Dell reservoirs will result in higher flows of Parleys Creek, and will be visible in the Parleys Nature Preserve, Sugar House Park and Hidden Hollow, officials said. These controlled releases help reduce runoff pressure on the city by maintaining upstream capacity in the Parleys watershed, officials said.
Salt Lake City Residents can call 801-483-6700 to report flooding.
