Sandy declares state of emergency due to flooding

City officials are concerned about fast-flowing Little Cottonwood Creek.

(Francisco Kjolseth | The Salt Lake Tribune) Avalanche debris fields illustrate a record breaking snow year up Little Cottonwood Canyon on Wednesday, May 17, 2023. Sandy officials declared a state of emergency related to flooding risk and mitigation on Wednesday, May 31, 2023.

The mayor of Sandy on Wednesday declared a state of emergency to help with flooding mitigation as Utah’s historic snowpack continues to melt.

The move from Mayor Monica Zoltanski opens up opportunities for the city to receive both state and federal resources to help address flooding issues caused by seasonally high levels of snowmelt east of the city, according to the proclamation. It will last for 30 days but can be extended.

Sandy’s efforts to mitigate this year’s higher flows along Little Cottonwood Creek began more than a month ago, the proclamation states, and mitigation efforts have extended into other drainages in Sandy, where debris can exacerbate flooding.

The proclamation is meant to show Sandy’s continued efforts at bracing for possible future flooding, especially as snow in higher elevations continues to melt, said Tom Ward, director of Sandy City Public Utilities.

“Rather than sitting and letting hope be our only plan, we wanted to make sure everyone was prepared,” Ward said. Efforts will continue until creek flows abate, the proclamation states.

But Brian McInerney, a hydrologist who consults with Salt Lake City, said Wednesday that based on current forecasts, he doesn’t predict flooding to be a catastrophic problem in the coming weeks along Big and Little Cottonwood creeks.

Both are predicted to flow at about 500 cubic feet per second, he said. Flooding is likely at 800 cfs, according to the National Weather Service. That’s the equivalent of about 800 basketballs flowing through a creek each second.

Flooding issues earlier this month were caused by an increase in bright sunshine, McInerney said. Less cloud cover at the time meant the snowpack melted more rapidly.

“Snow is a really good insulator,” he said. “It’s like a puppy coat. It doesn’t really feel the air temperature, but if you have a lot of sun, that energy infiltrates into the snowpack and produces some pretty high melt rates.”

Melt rates were as high as 2 inches a day through mid-May. But then the weather shifted, McInerney said. Thunderstorms that did not produce a lot of valley rain blanketed the area in cloud cover, which has slowed snowmelt.

Though some models show the creek won’t reach flood status in the next few weeks, Ward said he is wary of relying on them.

“Like any weather forecaster, a model forecast is never going to be accurate,” he said. “It’s going to be higher or lower.”

McInerney still warned that both Big and Little Cottonwood creeks remain unsafe to be around. He advised families not to take their children or pets near the creeks, because the water flows very quickly as snow continues to melt. If you fall in, it can be very difficult to get back out.

“I know we all want to put on flip-flops and go up the canyon and look at the water,” he said. “Stay away and wait for the water to come down.”

Most of the snow affecting the creeks is predicted to have melted by the second week of June, he added.

Sandy is the latest Utah city to declare a state of emergency related to flooding this year. Holladay officials made a similar announcement May 16 because of snowmelt in Big Cottonwood Canyon.

In April, both Salt Lake City Mayor Erin Mendenhall and Salt Lake County Mayor Jenny Wilson declared a state of emergency related to flooding. On May 1, Spanish Fork Mayor Mike Mendenhall issued a similar declaration.

Gov. Spencer Cox declared a state of emergency for Utah on April 18 because of ongoing flooding and flood risk. A month later, he convened state lawmakers to address flooding, during which they reappropriated $33 million in state funds to help expand and repair culverts, repair damaged bridges, purchase and distribute sandbags, monitor for landslides, staff the state’s emergency operations center and more.