Winter So Far Is Scary News For Snowpack, Summer Water Supply

Jan 14, 2021

The current winter season is not only facing the Covid pandemic, it’s also got to deal with the dismal snowfall that has occurred so far.

An analyst with the Natural Resouce Conservation Service says the outlook for snowpack is “frighteningly bad.”  That could be a serious problem for this summer.

KPCW talked to Jordan Clayton, Utah Snow Survey Supervisor with the Service, who said they need to see a turnaround with precipitation before the runoff season, which usually occurs from early April to the start of July.

He said currently the snowpack is well below average for the state.     And on the Wasatch Back, indicators aren’t good for the watersheds of the Provo River and the Weber.        

“All those watersheds are hovering around 40 to 50 percent of normal in terms of the snow-water equivalent.  That’s the amount of water that’s in our snowpack.  We’ve been getting these nickel-and-dime storms.  So, obviously the mountains have a little bit of snow, but it’s about half of what it would normally be at this time of year.  And that water equivalent in the snowpack is currently not gonna be nearly enough to overcome, again, the soil/moisture deficit and other factors to produce average runoff conditions.  So when all that snow melts, we’re expecting at this point well below-overage runoff.  Our forecasts in terms of runoff are generally in the 30 to 50 or 60 percent of normal range.”

He noted that very dry soil is a concern, because it can soak up moisture that would otherwise appear in the runoff.       

“What we really like to see is an above-average snowpack that melts somewhat quickly—not too quickly to produce floods—but somewhat quickly so that you have saturated soils, meaning that there’s really not much more room in the soil for the water to go.  And so most of that water then gets routed through the stream network and into our reservoirs.  When you have exceptionally dry soils like we have right now, they typically don’t change in their level of moisture or dryness through the winter months because they’re covered up by the snowpack, and there’s really not a lot of water coming in or out of them at that time.   And then once the snowpack gets to a point where it starts to melt, that water will be introduced into those little suction-cup-type soils where it’s gonna suck up a lot of that available moisture, and a lower percentage of it is gonna actually make it into our streams.”

Reservoirs have been drawn down, not just because of weak winter snowpacks, but due to the previous dry summer.

He said that Echo Reservoir is just over 60 percent of normal, and the Jordanelle Reservoir is above average.   Clayton said, though, that is not just the result of hydrology but also the water management of those areas.

“One way or another, our reservoir system has been impacted by the fact that we had now, two below-average snowpack years in a row.  Last year’s winter was doing pretty well until kinda early spring, and early spring the snowpack really turned off.  And quite frankly the precipitation never came back.  And we didn’t see any of our normal summer monsoons.   We had obviously extensive drawdown of our water-storage system, our reservoirs through the summer.  And so now we’re at a position where the year before, our reservoirs were still kinda holding over nicely from the previous year’s winter, going back now two years where we had done pretty well.  Now we drew them down last year and then we’re gonna draw them down again, to the point now where we really need to start to get concerned about holding back some of that water to make sure we have enough.”

He said his agency doesn’t make weather forecasts, although near-term, maybe the pattern could change towards the end of January.

Clayton said in order to get an average snowpack by April 1st, they will need 9 to 10 feet of additional snow across the state.   And they will need an above-average snowpack to get an average runoff.

He said the Conservation Service confers with a number of other agencies to make a drought assessment later this year.        

“Currently, the state of Utah is really in bad shape in terms of drought.   We have about 70 percent of the state that’s in what we would call D-4, which is exceptional drought, that’s the worst drought category on the list.  About 90 percent of the state is—actually, I think it’s 95, I don’t have the numbers in front of me—but it’s more than 90 percent of the state is in D-3 or D-4, extreme or exceptional drought.  So really there’s very, very little portion of the state that’s not in severe, exceptional or extreme drought conditions right now.”

Jordan Clayton, from the Natural Resource Conservation Service.

Tags: