They were a start, experts say, but a lot more storms are needed.
(Trent Nelson | The Salt Lake Tribune) Salt Lake City covered in fresh snow on Wednesday, Dec. 15, 2021.
| Dec. 18, 2021, 2:00 p.m.
The snowstorms that hit Utah this week marked a good start to rebuilding the state’s all-important mountain snowpack, dumping 1-2 feet of snow in some areas and considerably more in others.
But Utah is still behind, sitting at about 60% to 70% of what is considered median snowpack, according to Jim Steenburgh, a professor of atmospheric sciences at the University of Utah and an expert on mountain climate.
“What we really need is a multi-day storm cycle in the mountains to catch us back up to where we really want to be this time of year,” Steenburgh said.
Most of Utah remains in ‘extreme drought’
The latest report from the Utah Division of Water Resources, completed just before the big storm hit Tuesday night, showed that 78.71% of Utah remains in “extreme drought” conditions. Another 20.81% is in severe drought; 0.07% is in exceptional drought.
The snow water equivalent (how much water the snowpack would generate if melted) was at 2.8 inches as of Dec. 14. That’s 74% of the average for that date, and 18% of the average for peak snowpack, which usually occurs in early April.
This week’s storm did increase the danger of avalanches in the mountains — it is now “considerable” in the mountains near Salt Lake City, Logan, Ogden, Provo and Moab, as well as in the Uintas and the Skyline area, according to the Utah Avalanche Center.
But according to the National Weather Service, there is no precipitation in the forecast for Utah through Tuesday. The next chance for rain and snow is Wednesday — a storm that could break up the inversion that’s building in northern Utah’s valleys.
(Chris Samuels | The Salt Lake Tribune) Heavy snow bogs down traffic and residents in Salt Lake City, Wednesday, Dec. 15, 2021.
‘We lost a lot of it to sunshine’
Utah’s mountain snowpack was looking pretty good in October, when the state got 2-3 times its normal rainfall. Salt Lake City totaled 3.49 inches; it averages 1.26 inches.
“We were ahead of schedule,” David Church, the National Weather Service’s science and operations officer in Salt Lake City, said. “But then we got into November, and we didn’t have any [precipitation] for three or four weeks. That really set us back.”
So did higher than average temperatures. According to the Utah Division of Water Resources, the average temperature from Nov. 15-Dec. 14 was 4.8 degrees above normal, causing some of the snowpack to melt.
According to Church, Utah hit a record-low snowpack from about Dec. 1-9. A storm on Dec. 9 got the snowpack up to just below the 10th percentile. This week’s storms took the state to about the 20th percentile. (The 50th percentile would be average.)
“It’s kind of a bummer, because we had a decent amount of upper elevation snow in October. But we lost a lot of it to sunshine,” Steenburgh said. “So it’s kind of like a reset, where we’ve just started to build up the snowpack again, starting in early December.”
(Chris Samuels | The Salt Lake Tribune) A downed tree branch takes down a power line from heavy snow in Salt Lake City, Wednesday, Dec. 15, 2021.
More runoff possible this season
It’s not all bad news: Soil moisture is 16% above average for this time of year. If that holds, it could mean more mountain runoff in reservoirs come spring and summer.
“Last year, we had record dry soils going into the winter,” Church said. “And then we put a below-average snowpack on top of that. So when that melted off, a large amount of that runoff just went into the soil.”
“Basically, the soil sucked up maybe about half of that moisture instead of it running off into the reservoirs,” he continued. “That was key for the drought to continue to worsen.”
Because of improved soil moisture, “We’re in a much better place than we were last year,” Church said. “Whatever snowpack we do build up this year will be much more efficient as it runs off the next year — running into the reservoirs and not just soaking into the soil.”
The snowpack usually doesn’t hit its peak until early April, when it begins to melt. That generally continues until June.
“From a water perspective, building snowpack in the mountains is one of the most important things,” Church said. “In a way, it acts like a reservoir for us — a frozen one.”
But that doesn’t mean that Utah’s valleys need to be buried under snow over and over again through the winter. “If it just rains in the valleys and then we keep a lot of good snowpack in the mountains, that would be fine,” Church said.
“Mountain snow and valley rain works,” Steenburgh, who goes by “Professor Powder” on Twitter, said with a laugh. “I like snow in the yard sometimes. But a 5,000-foot snow level means less shoveling and less wear-and-tear on my back, but I still get to go skiing. That’s kind of the dream scenario.”