By SHEILA WANG • Standard-Examiner staff
OGDEN – The dry and fluffy Utah snow is at stake, as an analysis found winter has shrunken by two months in the past 100 years in Northern Utah, along with decreasing snowfall.
A century’s worth of records compiled by The Associated Press reveal winter cold in Northern Utah used to last much longer 100 years ago - more than two months longer - on average, as the spring starts early and the winter arrives late.
"There is no normal anymore," said Jim Steenburgh, atmospheric sciences professor at the University of Utah, attributing the shrinking winter trend to global warming.
Graphics below illustrate how the length of winter in Utah has changed over time in the past 100 years in different parts of the state and what it means to Utahns. The length of winter is determined by the first fall freeze day and the last spring freeze day of each year.
Winter returned late in Northern Utah this year, again, after leaving winter sports enthusiasts craving for cold for weeks.
Shrinking winter has already taken a toll on the ski resorts in Northern Utah, Steenburgh said, and the impact would become larger in the future.
"We’ll see a warmer climate system generally in the following decades," he said.
The graphic above illustrates the number of average winter days, the first fall freeze day and the last spring freeze day in Northern Utah from 1916 to 2016. The shaded chart shows a general trend of shrinking winter days in Northern Utah despite the fluctuations. The two line charts on the left and right respectively show a distinctive pattern of late winter and early spring.
This year, Ogden’s first fall freeze arrived on Oct. 15, or the 288th day of the year, when the temperature dropped to 32 degree Fahrenheit (°F), according to the National Weather Forecast Office in Salt Lake City. It would’ve fallen into a perfect normal range for first freeze days in Northern Utah for the past 10 years, but the day was evidently late, when compared to the first freeze day a century ago shown in the line chart on the left.
The chart shows the earliest day for the first fall freeze in the past 100 years was on September 6 in 1924, the 250th day of the year. That year Northern Utah also experienced the longest winter, as the freeze days averaged out nearly nine months. The year of 2015, on the other hand, marks the slowest start of winter in Northern Utah.
Since the early 1980s, it had become common for the first freeze to appear around early October, rather than September. In most recent years, the first freeze most often occurred in mid- and late October.
In contrast, the line chart on the right shows a less drastic change over time in terms of the last spring freeze day in Northern Utah. Generally speaking, the spring arrives earlier over time as well.
The shorter winter is "part of an overall global trend," Steenburgh said, and we're going to see more cold waves and heat waves as a result in the next 30 or 40 years.
The shortening length of freeze weather, however, is probably not the biggest concern in Northern Utah.
Snow, which Utahns take pride in, is also on the line.
“Precipitation comes more in the form of rain, but less in snow,” Dr. Robert Gillies, Director of Utah Climate Center, said in an interview.
The climatologist and his fellow researchers studied the weather pattern in Utah's winter and found that the statewide snowfall has decreased by nine percent over a half century, more so at lower elevations.
The ski industry is most likely to take a hit from the declining snowfall in Northern Utah, since most ski resorts are situated at mid-lower elevations.
When snow does come, it tends to come with storms, Gillies said, noting a tendency "toward stronger winter weather in terms of precipitation intensity" in Utah.
A number of ski resorts opened late this year due to the late arrival of the first snow. For instance, Powder Mountain Resort in Eden announced it would open on Christmas Eve this year — weeks after Snowbasin and Nordic Valley opened. The resort has opened after Christmas at least four times in the last 45 years, marketing manager Jean-Pierre Goulet said.
Northern Utah is not alone in the shrinking winter trend. The rest of state has also shared the phenomenon to various degrees, as the graphics below indicates.
The graphic above presents the changes in the length of winter in various parts of Utah based on the locations of the weather stations. Choose any location in the drop-down menu to see how winter has changed in any area.
You may see the length of winter fluctuates over the years and in general is becoming shorter.
There is a silver lining, Gillies said. "Shorter winter means longer growing season."
Farmers might be able to take advantage of the changing weather pattern as a longer growing season usually helps improve crop productivity. However, the benefit could be offset by another product of global warming – flooding.
Meanwhile, Gillies pointed out in his research paper a notable declining trend in Utah's springtime snowpack, which is "crucial for sustaining the region’s water resources."
To see a time lapse of shrinking winter in Utah, use the toggle on the map below to track how much winter has shrunken in your area.
Contact Reporter Sheila Wang at 801-625-4252 or firstname.lastname@example.org. Follow her on Facebook @JournalistSheilaW or on Twitter @SheilaWang7.