With Utah’s historic snowpack, Summit County officials prepare for flooding
Summit County’s mayors hold their monthly meeting Tuesday where they plan to hear from the county’s emergency management team.
Summit County Emergency Manager Kathryn McMullin will talk to the County Council of Governments about spring flooding preparedness and response Tuesday.
The COG consists of all Summit County’s mayors and a representative from the county council.
McMullin’s report states Oakley and Coalville have drafted specific action plans in the event of flooding. Both areas were flooded by the Weber River back in 2011, the most major recent flood in the Wasatch Back.
Communities including Heber City and Coalville have made sandbagging a priority in recent weeks. McMullin’s report estimates the county has 28,000 bags available, and individual cities and towns also have about 1,000 each.
North Summit firefighters helped pre-fill sandbags at the Coalville Public Works building last Thursday and will continue to help fill bags until the flood risk subsides.
But what kind of risk does the county really face? Summit County’s Local Emergency Planning Commission met March 7 to assess.
Those local officials heard from hydrologist Glenn Merrill and meteorologist Kevin Barjenbruch from the National Oceanic and Atmospheric Administration, which oversees the National Weather Service.
Merrill said the ideal scenario is a long, somewhat wet spring that brings down water from the mountains in chunks.
"Where we get a storm and then we warm up right behind it, and we start peeling it down. And then we cool down again, lock it up—then warm it up— and then cool it down, lock it up. So we kind of want it to be a stair-step style,” he said.
Merrill said he asks himself three questions this time of year: when will snowpack peak, how tall will that peak be and when will things warm up?
The first question is impossible to answer for sure, but snowpack usually peaks in the first week of April. During historic flood years in 2011 and in the 1980s, snowpack peaked later in May.
But the second question has a more certain answer: peak snowpack will be historic this year. That’s measured with what’s called “snow water equivalent,” which refers to how many inches of water Utah’s snowpack contains.
Last week Utah hit its highest-ever level of snow water equivalent for late March: 24 inches. In the Wasatch Back, snowpack numbers are not quite historic, but are getting there.
Merrill observed the area has more snow at lower elevations than in 2011. The western Uinta Mountains are effectively covered in 30 inches of water right now, and the Wasatch Mountains have even more.
But what about that third question: when will things warm up? Unfortunately, Merrill said that’s another big question mark.
What he did say is Utah has been colder this year than it has been in recent years, colder than the historic average by about two degrees across the state.
If those temperatures reverse quickly, coupled with a later peak snowpack, then flooding will be extreme. Merrill recalled the sudden high temperatures Utah saw in 1983.
“We don’t want to see what happened in the early '80s where we peaked late May, and then on Memorial Day weekend it was 90 degrees in the Salt Lake Valley and 80s up here [in Summit County],” he said.
The good news is—thanks in part to extreme drought—reservoirs have capacity to take on more water right now, and some areas have dry soil ready to soak up water.
Two areas of note are too saturated to soak up runoff: the Smith Morehouse area above Oakley and the Chalk Creek area above Coalville.
Barjenbruch compared water data to market forces—not under anyone’s control, at least immediately.
“That's kind of what I want to do, is just let everybody know, ‘Hey, these are tools you may have to watch, just like the stock market,’” he said.
In the meantime, county officials are formulating emergency response plans and making things like sandbags available to residents.
Click here for NOAA’s live map of snow water equivalent.
Click here for the Utah Snow Survey Program.
Sandbagging stations have been established at the Summit County Public Works Complex, Kamas Public Works, Coalville Public Works, Oakley City Recreation Complex, Francis Public Works, Henefer City Park and Park City Public Works Building.
For more information, visit https://summitcounty.org/flooding.
At the time of this update, the county had about 25,000 sandbags on hand for residents to fill. Unless otherwise noted, fill stations are "bring-your-own-shovel."