Winter doesn’t feel like it’s behind us, but technically it's already spring.
But how did this year’s winter season stack up against previous ones, and what can it tell us about the rest of the year? Alaska Climate Specialist Rick Thoman said that there are clues in the data.
Thoman said that it’s been a near-normal winter overall if you just look at the long, multi-month average for both temperature and precipitation.
“But I'll bet almost no one thinks that because, to me, the highlight was the ups and downs. There was some cold, cold weather; there was very mild weather. That variability that was repeated, it's not like the first half of winter was particularly warm,” Thoman said. “And then the second half was particularly cold, you know, every week or 10 days it seemed like there was a major weather pattern change.”
That temperature variability can wreak havoc on infrastructure. This past winter KYUK reported on frozen pipes shutting down the laundromat and the fitness center, and schools were closed or delayed due to road conditions. Even Bethel Search and Rescue had to close the ice road on several occasions due to open water. And then let's not forget the pendulum swing in temperature at the K300.
“So when we have these highly variable conditions, and particularly on the Kusko[kwim], with the comparatively mild November and early December. And so freeze up pretty late, and having those, you know, the problem areas, the areas with weak ice or holes persisting relatively late, that's obviously always a big concern for the [Y-K] Delta,” Thoman said. ”And this variable weather patterns certainly contributed to that.”
Thoman said that as we head into April the variable weather will continue, which is a cause of concern. While the snowpack on the Y-K Delta is near to even below average, there's as much as one and a half times the normal water in the snowpack above Kalskag.
“In some parts of the upper Kuskokwim drainage, there's actually more water content in the snowpack than there was last year at this time. That doesn't mean there's going to be flooding problems, but it means it's something we really need to watch,” Thoman said.
Flooding and temperature changes not only impact those who live in the Y-K Delta, but it affects the ecosystem as well. Thoman said that anytime you get rainfall followed by a freeze, the tundra is essentially sealed off by that thick layer of ice. That’s a problem for animals that rely on the tundra surface vegetation as a food source. And what about the fish? That depends on whether it’s an orderly breakup or not.
“The fish are kind of evolved, that's part of life. But it's, I think we've seen problems. When we have, for instance, an early start, and then it gets cold and it kind of puts the brakes on, and then things are kind of stuck for a while and then get going. That certainly could happen again this year, given the variability in the weather pattern that we've seen all winter,” Thoman said.
As we head into the spring and then into the summer, there’s always a fire danger, but the severity depends on the snowpack. Thoman said that the snowpack is definitely below normal in the Y-K Delta from about Bethel to the coast.
“If we get early snow melt, you know, in the ground, that tundra vegetation starts drying out sooner; that increases the chance for wildfire. We also need to get warm and we need to be dry, like we had last spring, and then you have to have a spark. You need those thunderstorms,” Thoman said. “So you have to get all of those ingredients to come together.”
Historically, that hasn’t happened very often.
“But we know in the Y-K Delta that since 2015 there's been a complete change in the wildfire regime,” Thoman said. “And doesn't mean that every year is a big wildfire year, but it's a threat in a way that prior 10 years ago we never thought about. And that low snowpack that we have on the [Y-K] Delta right now, that, to me, is a warning sign that boy, we're going to have to pay close attention.”
Another cause of concern is the level of sea ice. Thoman said that the Bering Sea ice did not get as far south this year as it did last year. South of the ice edge where the ice didn't get to the ocean water, Thoman noted that temperatures all winter have been significantly warmer than normal.
“As much as over two and a half degrees Fahrenheit above normal, kind of an outer Bristol Bay, so south of Kuskokwim Bay. And those warm ocean temperatures, if those spread northward, as the ice melts and retreats this spring, you know, those very warm ocean temperatures could have a significant impact on our weather going into summer. And of course the open question, you know, what effect does that have on the fish out in the oceans as well?” Thoman said.
These warm temperatures all winter south of the ice edge could wind up being a major factor for Y-K Delta weather in the coming months.
