Data (might) beat our weather stories

Data (might) beat our weather stories

"Alaskans like to tell weather stories, and we've got a lot of weather to tell stories about," climate specialist Rick Thoman quipped over cups of cooling coffee.

I was raised in Fairbanks by parents who were also raised in Fairbanks, and I've heard versions of these stories my whole life. Stories like: We never used to have rain-on-snow events. Summer and autumn used to be less rainy. Winters just used to be a lot colder.

I have no real reason to doubt my parents' honesty and memory. However, I've recently started to wonder: How accurate are these stories, anyway?

Fortunately, Thoman was just 30 seconds down the hall. With 43 years working in weather and climate, Thoman is known for his encyclopedic knowledge of Alaska's historical climate data. He now works for the Alaska Center for Climate Assessment and Preparedness, housed within the University of Alaska Fairbanks International Arctic Research Center.

Once settled in Thoman's office, I asked, "What are Alaskans getting wrong about our changing climate? And what are they getting right?"

For many Fairbanksans, Thoman included, there is nothing more upsetting weather-wise than rain falling on snow in the winter. Surely my parents never experienced these winter rainstorms while walking uphill both ways to school at minus 60, right?

Thoman surprised me by saying that, according to historical data, Fairbanks experienced a spike of rain-on-snow events in the 1920s and '30s, and again in the 1960s.

"What's completely new now is that almost every winter we have at least one of these rain events. For most of this century, with the exception of last winter, they're happening with regularity," Thoman said.

In other words, while winter rain isn't unheard of in Fairbanks, it's now the new normal.

Another common Alaska weather story is that summer and autumn are rainier than they used to be. It seems like the past couple of summers and into September have indeed been drearier than average, creating the impression that June is now our only month of the year that is snow-free, reasonably warm and sunny.

"So, we have had a run of rainy summers," Thoman said, "but we've also had some big wildfire seasons. Those two don't really go together.

"Overall, there's not a lot of trend in total summertime precipitation over multiple decades."

Although there isn't yet a clear trend, Thoman mentioned that summer and autumn in Interior Alaska may eventually become truly wetter, due to warming ocean temperatures and a subsequent increase in atmospheric moisture.

So, why might some Alaska weather stories not fully align with reality? Thoman shared a few possible explanations with me.

An extreme weather event - a notably wet July or an exceptionally cold spell - can become representative of an entire season, or even several years.

"Here in Fairbanks, if you ask people of a certain age about the 1980s, they often rush to assert, 'Oh, it was really cold in the eighties,'" Thoman said.

In Fairbanks, the 1980s were bookended by an exceptionally cold December in 1980, and an even colder January in 1989. However, Thoman noted, Fairbanksans experienced some of the warmest winters on record between these two memorable months.

Another explanation for why we misremember is that, according to Thoman, "our brains have not evolved to be logbooks."

"There are big evolutionary advantages to generalizing patterns so you can make short-term predictions. You do that successfully, and you might get a better chance to survive," Thoman said.

In Fairbanks, Thoman emphasized, we are fortunate that people have recognized the value of carefully logging weather and climate for over a century.

"That kind of recordkeeping is invaluable to help understand what's really happened. We haven't evolved to integrate two lifetimes' worth of environmental change," Thoman said.

However, when it comes to noticing shifts in seasonality, some Alaskans are definitely getting it right. Farmers and those relying on a subsistence lifestyle are closely attuned to our shifting seasons, which affect crop success and hunting on land and on diminishing sea ice.

Oh, and my parents' story about how winters "just used to be colder"? That one holds up: Between 1949 and 2020, Alaska's average winter temperature increased by 7 degrees Fahrenheit, and extended periods of extremely cold temperatures are now not as common as they were during those all-uphill commutes of old.

Although we're lucky to have Thoman to guide us towards the truth, it would be a shame to toss our time-honored tradition of building community by connecting over weather woes, whether they're accurate or not.

However, be careful if you want to commiserate with data-loving Thoman.

"I'm not very popular at parties," he said with a laugh.

Since the late 1970s, the University of Alaska Fairbanks Geophysical Institute has provided the Alaska Science Forum column free in cooperation with the UAF research community. Sara Wilbur is a communications coordinator for the Geophysical Institute public information office.