OGDEN — The weekend storm that dumped 4 inches of snow in much of Top of Utah has given ski resorts hope, but not the state’s water managers.
History is not on their side.
While National Weather Service Hydrologist Brian McInerney is quick to say nobody can predict the weather beyond five days, he said history tells him that when the first half of winter is as dry as this one has been, it stays dry.
And it is very dry.
The National Soil Conservation Service issued its monthly water supply report Monday, saying December 2011 was the driest December on record.
“This year’s adjective is ‘wow!’ ” says the report written by Randy Julander.
“Could it get any worse? Record or near-record low snowpacks at 19 SNOTEL sites in central and northern Utah. Snowpacks are in the 40 percent to 70 percent of average range with nary a decent storm in sight and wolves howling at the door.”
SNOTEL sites are automatic snow-measuring locations that determine how much, how deep and how wet the snow is every winter. They are the weather service’s primary tool for predicting Utah’s water supply for the coming summer months.
McInerney said December was the driest since records have been kept in the weather service office in Salt Lake City, going back to the 1920s.
Out of curiosity, McInerney said, he checked records for other dry years to see not only what the dry Decembers looked like but also the two months before them and how the winter played out.
The previous driest water year on record was 1977, he said, both in the months from October through December and again through April.
The second-driest October-to-December stretch was in 1987, but enough snow fell later that, by April, it was the fifth-driest on record.
The 1983 water year was third-driest on record through December, and stayed third-driest through April.
However, Julander, in his water year report, takes a more optimistic view.
“When a water year starts out this poorly, there is a high probability (note that is not a 100 percent certainty) that snowpacks will improve before April 1,” he wrote.
“1980 started out nearly as bad as current conditions and ended up with an April 1 above average (120 percent to 180 percent).”
So it can go either way, and nobody can predict which.
McInerney said Utah needs multiple storms of three to five days each to catch up, but there’s no way of knowing if that will happen.
Despite the lack of snow, both Julander and McInerney said the state’s water situation has two things in its favor.
First, Julander said, streams flowing to Utah’s reservoirs are still above normal because of the high amounts of snow and runoff from last year. Coupled with that is, the reservoirs statewide are only 16 percent below full.
Julander said that means even a bad snowpack will still fill the reservoirs, which hold enough water to get the state through two years of water usage.
Second, McInerney said, models and data show that the soil moisture in the mountains, a measure of how wet the dirt is, is still good.
That means, when the spring thaw comes, more of the water in the snow will flow to streams and less will soak in.
“For (the Weber River’s drainage area), 70 percent of normal (stream flow) is what we’re calling for,” he said, even though snowpack is only 50 percent of normal. “So it’s higher than where the snow is because the soil moisture is higher.”
McInerney said one thing he hasn’t researched is whether a record-setting wet year, like last year, is often followed by a record-setting dry year, like this year.
He said climate-change researchers say that one sign of climate change’s effect on the weather is more extremes in both directions, with generally drier and hotter winters but occasional extremely wet and cold winters.
Whether last year and this year are a sign that is happening is unknown, he said. Only years of historical data can show the trend.
For now, he said, “We’re setting records. We had the wettest March-May, and now we’re dry? That’s messed up.”