FAIRBANKS — Temperatures in Alaska’s second-largest city dipped to the extreme last week but a weather expert who monitors them says legendary Fairbanks cold snaps are less frequent and less severe.
Temperatures in some parts of Fairbanks reached -40 (-40 Celsius), Alaska's Energy Desk reported , but didn't stay there long. Climate change and other factors have made cold snaps shorter and rarer.
Rick Thoman, a climatologist at the University of Alaska Fairbanks, said that the definition of a cold snap is somewhat "in the eye of the beholder."
When he mapped out the "great cold snaps" using the Fairbanks weather record, he defined it as weeks when temperatures averaged -40 or colder.
"Cold, like so many other environmental hazards in Alaska, is often cumulative," said Thoman. "So one cold day, OK, you just get through it. But after several days of deep cold, as things start to really freeze up, the impacts grow."
Over the last 80 or so years, he said, there's been a noticeable change. More recent cold snaps have been less frigid and less prolonged.
Mary and Dick Bishop, who arrived in Fairbanks in the fall of 1961, experienced the city's most intense cold snaps that December. The community averaged about -54 (-47.8 Celsius) for the last week of the month.
"Nothing's bad after that," said Mary Bishop, laughing. "We got quite an initiation."
They said there's a list of challenges that come along with that cold.
"Your tires are flat on one side," said Dick Bishop, "and all the cars just didn't start."
"We had minimal insulation in (our) house," said Mary Bishop, "and our young boys just lived in snowsuits."
In 50 years of living in interior Alaska, the Bishops agreed that cold snaps are less frequent.
Climate change is a significant factor, Thoman said, but others also play a role. One is related to urban growth, especially more cars on the road.
"Cars put out a lot of water just from burning gasoline, and that helps thicken up ice fog," said Thoman. "And ice fog, believe it or not, is actually a pretty good blanket."
That's a relatively small piece of the equation, Thoman said. Data from other places in the Interior without population increases also have been warmer.
Natural variability also plays a part, Thoman said. Multi-decade cycles in the atmosphere and ocean can be more or less conducive to creating super-cold weather.
However, natural cycles have gone through at least one full rotation since the 1970s, Thoman said.
“We have not seen a return to the temperatures or the frequency of the cold snaps that we saw before that.”