The rain has been nice. Utah will need more to fend off its drying soil conditions

Even though much of Utah saw heavy rain this week, the state’s soil is drying out. That could be bad news for next spring’s runoff season.

Soil moisture is “a little bit below normal,” and that worries Jordan Clayton with the Utah Snow Survey.

“That's masking a pattern that's showing that it's clearly drying from above at this point, and it's going to continue to do that until we get sufficient monsoonal moisture.”

This year’s hot and dry summer has led to soil conditions similar to what was seen in 2020 – when dry soil combined with a less-than-snowy winter led to reservoirs getting less than half of their expected runoff in 2021.

“What happened that year is we went into that winter with those abnormally dry, actually historically dry, soils and then we wound up with a runoff response the following spring of around 20 - 50% of normal runoff in most of our locations,” Clayton said.

“It was really, really poor, and it's part of what kicked us into those three years of really being in frighteningly low water supply conditions, up until last winter, when we had the historic snowpack.”

That pattern could repeat this year if more moisture doesn’t fall before winter sets in.

According to the Natural Resource Conservation Service, statewide soil moisture at the service’s Soil Climate Analysis Network sites ended July at 39% of saturation. That’s in the bottom 10th percentile since the sites were installed.

Despite a dry July, the rains have been generous since Aug. 12. That moisture has others, like Utah Division of Water Resources Drought Coordinator Laura Haskell, hoping to see more wet weather as we move into late summer and fall.

“If we can have some consistent storms and some lower temperatures to keep that soil wet, then it'll be in a much better condition for next spring,” she said.

Soil moisture is critical to a successful spring runoff season. Haskell says to think of dirt “like a kitchen sponge.”

“So your snowpack is sitting on this kitchen sponge, and as your snow starts to melt, if your kitchen sponge is really dry, it's just going to soak into that kitchen sponge, and if it's really wet, then it's going to leak all over your kitchen counter, and that's what we want. We want that water to go off and run into streams and run into our lakes.”

The good news, Haskell said, is that Utah reservoirs are collectively 18% above normal right now. That gives the state some cushion in case this winter is not a wet one. Even then, “each reservoir is a little bit different.”

“There are some reservoirs that could be up to 10 years of water storage. There are other reservoirs that are only a single year of water storage for that local area that they serve.”

According to the U.S. Drought Monitor, 89.4% of Utah is experiencing conditions that are “abnormally dry” or worse.

“We’re really hoping that the monsoonal pattern kicks in and brings a lot of moisture to Utah,” Clayton said.

“We're just going to kind of keep our fingers crossed.”