SALT LAKE CITY — Multiple dams in northern Utah are operating in a flood control mode as managers of water systems are engaged in a juggling act to release enough water to make room for snowmelt but not too much so downstream communities don't flood.
"There is still 180 percent (of normal) snowpack in Monte Cristo area and, accordingly, we have been releasing water out of Pineview Dam," said Tage Flint, general manager of the Weber Basin Water Conservancy District.
Flint said 40,000 acre-feet of water has been released so far from the dam into the Ogden River, pushing it just within reach of flood stage.
At East Canyon Dam, fed by a huge watershed, Flint said he expects the dam to spill at some point during the spring runoff — which hasn't happened in years.
"That is one of the most difficult reservoirs in our system to fill. That all has to do with the size of the watershed above because it practically drains all the Park City ski resort area," he said.
Flint said it takes an above average snow year to fill the reservoir.
"We have been holding it somewhat level so there is room in it, and it can take on the big surge when the runoff starts in earnest," he said.
The latest snowpack and climate report released Wednesday by the Natural Resources Conservation Service details the staggering numbers associated with this year's snowpack.
In March alone, for example, the Bear River inflows were 120,000 acre-feet. Compare that with entire spring runoff flows in drought years at numbers such as 18,000 acre-feet, 22,000 acre-feet or 10,000 acre-feet. An acre-foot of water is enough water to cover an acre of land, or about a football field, with 1 foot of water.
While last Saturday marked the end of the snowpack accumulation season, hydrologists are all too aware that Mother Nature doesn't always follow the calendar.
The National Weather Service in Salt Lake City is predicting this weekend's wet storm to come with possible significant accumulation of snow in the mountains.
Snowpack, meanwhile, remains at above-average levels, with the Bear River Basin at 168 percent of normal, the Weber-Ogden River Basin at 145 percent, Provo-Jordan at 137 percent and Tooele at 133 percent.
That means a lot of water is left to come in areas across northern Utah, including Box Elder and Cache counties, which already sustained damages of $6.7 million to public infrastructure from February flooding and received a disaster declaration from Gov. Gary Herbert last week.
The snowpack report warns that the worst scenario that could play out is a cold, wet spring that suddenly warms up, with above-average temperatures that bring the snowpack down in a rush.
"We know the flows are going to be high in every stream," Flint said. "Everything that is above a dam and cannot be controlled" is at risk of flooding.
The good news is Cache and Box Elder counties have had a chance to dry out over the past month, leading to conditions that somewhat alleviate flooding and mudslide potential.
The warm stretch of weather in March also helped bring down lower elevation snowpack.