California isn’t the only state where record snowfall this winter has delighted skiers and raised concerns about the potential for spring flooding. While the Golden State has been the first stop for a constant barrage of storms intensifying over the Pacific Ocean, much of that precipitation has spilled over into the Mountain West, dumping heavy mountain snow across portions of Utah, Colorado, Arizona and Nevada.
A snow season that started early has turned into a record-breaker for many locations, with over 700 inches at some Utah ski resorts and snowpack more than 300 percent of normal, in a region where snow accumulation sometimes continues into May. To the south, Flagstaff, Ariz., has seen its snowiest winter in more than 40 years with nearly 160 inches thus far. “Many people living here today have not seen a winter like this,” said the National Weather Service office in Flagstaff in a tweet.
In Reno, the 32 days with snow at the airport since Oct. 1 has surpassed the record of 30 days in 1921-22.
All this snow has reduced drought concerns and filled reservoirs after a series of relatively dry winters, but has also increased the risk of avalanches and could lead to flooding as the snow melts this spring.
“It’s fairly likely that there will at least be some localized flooding,” said Jim Steenburgh, a snow expert and atmospheric sciences professor at the University of Utah. “More serious flooding will depend on the weather over the next few weeks.”
Dramatic footage of an avalanche near Provo, Utah, earlier this week went viral, receiving over 2.1 million views on Twitter. No one was hurt in the incident.
Ski season starts early, ends late
Early-season snow and cold allowed Utah’s Snowbasin Resort to open for skiing on Nov. 18, its earliest opening on record. Other ski resorts in Utah, Colorado and Nevada opened early as well. At the time, there was no indication of the onslaught of snow to come, with the National Oceanic and Atmospheric Administration predicting drier-than-normal conditions, or equal chances of drier- or wetter-than-normal conditions, across the region.
More than four months later, after as much as 65 feet of snow, some of the same resorts have announced they will stay open later than scheduled. Snowbasin plans to stay open through April 23, while Brighton Resort and Solitude Mountain Resort will operate into late May. For Snowbasin, which first opened in 1940, the expected total of 156 ski days would be its longest season ever.
Several ski resorts in Utah have recorded their highest seasonal snowfall totals on record, and the snow season isn’t done yet. Brighton, Solitude and Alta Ski Area have all reported more than 700 inches on the season. Earlier this week, Chase Thomason, a meteorologist at KUTV in Salt Lake City, posted the following list of Utah ski resort snow records on Twitter:
Seven Utah resorts have announced their all-time snow records have been broken this season. What a year! #utwx pic.twitter.com/8BqiSsAdfa— Chase Thomason (@ChaseThomason) March 27, 2023
To mark the momentous amount of snow, the Hyatt Regency Salt Lake City has unveiled a banner outside the hotel that shows what 700 inches of snow looks like.
“I think it is a near certainty that Alta will exceed 800 inches for the year,” Steenburgh said. “Whether or not they can push 850 or 900 is the question.”
Meanwhile in Colorado, Steamboat Ski Resort had already recorded 333 inches by the middle of February, more snow than all of last season. By March 23, its snowfall total was up to 401.5 inches, starting to close in on the record of 489 inches in 2007-08. Steamboat is among several Colorado ski resorts, including Monarch Mountain, Aspen Mountain, Aspen Highlands and Copper Mountain, that plan to extend their closing dates.
Snowpack snuffs out drought, but will it set stage for flooding?
Utah’s statewide average snowpack, as measured by the amount of water contained in the snow, is at a record high at just over 27 inches. Snowpack across much of the state is near or more than 200 percent above normal for the date, and just over 300 percent of normal in the southwest corner of the state
In Arizona’s Verde River and Salt River basins, snowpack levels have topped 500 percent of normal. The state’s reservoir system is now running 102 percent full compared to only 71 percent a year ago. Colorado snowpack is running above normal as well, for the first time since 2019, with a statewide average just over 140 percent of normal.
Last year on March 27th we were breaking temperature records with a high of 79 at the SLC airport. This year we are breaking snowpack records across parts of the #ColoradoRiver basin. It's pretty incredible to see the difference between the two years. #utwx #cowx #azwx pic.twitter.com/9Ph39KuVKO— Colorado Basin RFC (@nwscbrfc) March 27, 2023
Drought conditions have improved dramatically for much of the West. At the beginning of the water season in early October, the U.S. Drought Monitor classified California, Nevada and Utah under severe, extreme or exceptional drought, the three worst categories. But in the latest report, released today, extreme and exceptional drought have disappeared, while severe drought only covers a relatively small portion of those states.
How fast temperatures warm and how quickly the snow melts this spring will determine how much flooding occurs.
“Minor to moderate flooding is forecast or occurring in portions of central Arizona, far eastern Nevada, and in western Nevada along eastern slopes of the Sierra Nevada to due a combination of rain and snowmelt,” said the National Weather Service Office of Water Prediction in an assessment issued March 16. “Minor flooding is also possible in basins across northeast Utah, western Colorado, and southcentral Wyoming ...”
The more sudden the transition to spring, the higher the risk of flooding, according to Steenburgh.
“A best-case scenario will be a shift to a drier pattern with a gradual transition to near-average spring temperatures,” Steenburgh said. “A worst-case scenario is one in which we stay cold and snowy into May at upper elevations and then shift to a hot, dry, sunny pattern.”