Utah’s balmy winter weather may have you ready to throw out your winter coat, but hold that thought, at least for a few more decades.
The state has been breaking heat records for months and is nearing a record low for snowfall. It’s been the kind of winter that current climate models suggest Utah will experience more frequently in the future. But local weather experts don’t think this year’s weather represents the norm — not yet, at least.
It’s been much too warm for that.
“I don’t think this is the new climate normal,” said Jim Steenburgh, a professor of atmospheric sciences at the University of Utah. “This is an unusual year, even with the warming we’ve had. It would still be abnormal 20-30 years from now, but the potential for years like this is growing.”
Since November, Utah has experienced the hottest winter in recorded history, Steenburgh said. Temperatures measured at the Salt Lake City International Airport averaged nearly ten degrees above normal last month, according to Brian McInerney, a hydrologist for the National Weather Service in Salt Lake City.
Climate change is expected to increase average temperatures in Utah by about 12 degrees, McInerney said. But that’s not supposed to happen for nearly a century. And the temperatures Utah is seeing right now? McInerney said 9-degree warmer winters aren’t expected to become the norm until 2090.
So why is it so hot and dry? Local experts say Utah is once again stuck beneath a persistent ridge in an atmospheric air current known as the “jet stream.” When that high-atmosphere stream moves south, it brings cold, stormy temperatures with it. And when it shifts north, the jet stream dumps winter someplace else — the frigid East Coast, at the moment.
Snowpack has taken a major hit. While it’s still a little early to determine whether this will be the driest winter on record, Troy Brosten, a hydrologist with the Natural Resources Conservation Service, said it’s certainly going to be among the worst.
With the exception of northernmost reaches of the state, most of Utah has accumulated less than half as much snow as it usually expects during the winter. And the odds that a late-season snowstorm brings Utah back within normal range are less than 10 percent, McInerney said.
To make water prospects worse, warm weather has already started melting snow at lower elevations. There have been drier winters, Steenburgh said, but “this is close to as bad as it gets.”
It’s not the first time Utah has seen the jet stream playing wintry keep-away, either. Before the heavy snows of 2017, a similar fluctuation in the jet stream caused a drought that persisted in most of the state for nearly three years.
This seems to becoming a pattern, Brosten said.
“I feel like we’re seeing, either really big years, well above average years, or well below normal years,” he said. “We’re seeing extremes, one end or the other, but we’re not seeing much of a normal year, and that’s been the pattern for the last 7-8 years.”
So, is that caused by climate change? Perhaps, the experts are saying.
There is a developing theory that an increasingly unreliable jet stream may be tied to a loss of sea ice. But that remains a theory, and Steenburgh said he was inclined to attribute this latest dry winter to bad luck.
“I wouldn’t expect more years like this, but no guarantees,” he said, adding that tree ring records indicate that in the distant past, Utah endured dry periods that lasted far longer than anything observed by humans today.
McInerney agreed that this year is probably a fluke. But if the prevailing science is correct, he said, Utahns are now getting a glimpse of the weather their children and grandchildren will one day experience.
“I don’t think this is the new normal yet, but it’s where we’re headed,” he said. “That doesn’t mean that every year is going to be like this, but progressively that is the trend.”