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An unseasonably warm winter is now an unseasonably warm spring. This year’s equinox ushered in record-setting temperatures across the West, including in the Tetons.
“We’ve been seeing temperatures 25 to 30 degrees above average,” OpenSnow meteorologist Alan Smith said.
The early-spring heatwave comes amid a strong high pressure system, on the tail-end of extreme wind activity. That combination has returned again this week, prompting a fire watch and red flag warning in effect across most of the state on March 25, according to the National Weather Service office in Riverton.
Last week, Jackson reached a record daytime high for March at 73 degrees Fahrenheit degrees while the airport north of town hit 70 degrees. Smith said the average high this time of year is typically 42 degrees.
Jackson clocked three days in a row of temperatures at 70 degrees last week. That came from an “unusually strong” high-pressure ridge above the West and warmer air masses all winter, Smith said.
The last time Jackson saw temperatures that high in March was in 2004. Though unlike this year, that unusual warmth only lasted a day.
The surrounding region also hit records for March, Smith added, with temperatures reaching 76 degrees in Idaho Falls, Idaho, 82 degrees in Lander and 83 degrees in Casper.
That puts warmer temperatures about six weeks ahead of schedule or what the Tetons might more typically experience in May, Smith said.
But he and Wyoming state avalanche program supervisor Donald Lawless are staying braced for April.
“It feels really nice to have 70 degrees down in the valley,” Lawless said. “I’m trying not to switch my mindset into more of a summer mode right now.”
The Wyoming Department of Transportation has seen “big Aprils” before, he said. Jackson Hole Mountain Resort sees on average four snow days each April, racking up 20 inches of precipitation, according to OpenSnow, which has eleven inches of snow forecast for the next six to 10 days.
Smith said the mountain’s Rendezvous Bowl plot averages 58 inches each April, meaning next week’s snow showers could help get the mountain closer to par with late springs of the past.
The Tetons’ backcountry skiers usually indulge in longer days and steeper lines this time of year, but that season could feel a little short this year, with less reliable overnight freezing temperatures, even up high last week.
“It would be one thing if [you] had a day or two, once in a while, where you didn’t have a freeze during a warm spell,” Smith said. “But for it to happen like this consistently is very unusual.”
Smith said this winter was forecasted to see warmer and drier temps in most of the west. A weak La Niña climate pattern with an easterly quasi-biennial oscillation, a wind pattern, can cause colder, snowier weather in the northeast but leave the Rockies high and dry.
While one year doesn’t signify a trend, Smith said the weird weather this winter, and now spring, is still part of a larger overall trend toward warmer winters and extreme weather events.
“I’m not going to say that this entire winter was because of climate change, but I think there’s no way it didn’t play at least somewhat of a role,” Smith said.
Sophia Boyd-Fliegel contributed to reporting. – Ed.
