Chilly temperatures, snow showers and temperatures just below freezing. That’s the type of normal winter weather most Bartholomew County residents expect this time of year.
While that is what we experienced late last week, forecasters are predicting highs back well into the 40s this week.
Cold spells might shorten memories, but overall, the winter of 2019-2020 has, to date, been one of the mildest the area has experienced in several years.
But mild winters do have consequences.
Since it now appears likely the local region will not get the prolonged deep freeze it needs to kill off many bugs and pests, insects will be out earlier than expected this spring, multiply in greater numbers, and grow larger than normal, according to the National Wildlife Control Operators Association (NWCOA).
“There are going to be a lot more insect and pest problems,” said Cora Carter, who is agriculture, natural resources and community development extension educator for Bartholomew County.
There are several reasons why this winter has been unusually mild. One reason is ocean surface temperature trends in the Pacific Ocean near the equator, said Cummins Inc. retiree David Epperson, who holds a doctorate in atmospheric sciences from North Carolina State University.
These trends have a significant impact on south central Indiana weather because the continental U.S. lies in the prevailing westerly air flow coming off the Pacific, Epperson said.
Trends can bring in either milder air, or cause wild swings in the weather if they result in the jet stream moving in different places, Epperson said.
If you look back over the past four months, it appears Old Man Winter popped in early, but didn’t hang around long, Epperson said.
It became unusually cold on Halloween (Oct. 31), as well as the days surrounding Veteran’s Day (Nov. 11), Epperson recalled. In addition, Columbus also had a mid-November snow storm that iced up roads and dropped temperatures below 10 degrees, he said.
But as Thanksgiving approached, the sea surface temperatures got warmer, and a weak El Nino capable of splitting jet streams moved into North America, Epperson said. That’s when we began to experience warmer than average temperatures, he said.
From Dec. 21st through Jan. 30th, official statistics for Columbus measured only a tenth of an inch of snow. During that same period, temperatures have averaged 38.9 degrees, or 9.6 degrees above the 1981-2010 average of 29.3 degrees, Epperson said.
On both Christmas Day (Dec. 25) and Groundhog Day (Feb. 2), temperatures reached into the mid-60s.
While south central Indiana will likely experience occasional cold days through next month, the weather patterns established in January will likely continue through February, which means a continuation of above normal temperatures, Epperson said.
Forecasts indicate some rain over the next few weeks, but it does not appear that snow or cold will linger long in our area, he said.
Insects like stink bugs, boxelder bugs, cockroaches, ticks and termites can become active during warm winter days, according to the NWCOA. And after a mild winter, pests such as moths, mosquitoes, spiders, beetles, bees and wasps tend to reproduce earlier in the spring, grow larger than normal, and multiply in greater numbers, the association states.
That increases the odds of more pest-related crop, structural and ecological damage — especially if south central Indiana experiences drought conditions later in the year, the NWCOA states.
The good news is that this is Indiana, and with six weeks of winter left, “there can always be a surprise,” Epperson said.
If temperatures get cold for several days without snow to serve as an insulator, root damage might result in minor damage to a few bushes and trees, Carter said
“But nothing so bad to get worked up about,” the extension educator said.
Carter is far more worried about what might happen if a severe cold spell arrives in late March or early April after trees and flowers have started to bloom. The potential damage to plant life would be far more severe under those circumstances than anything resulting from a mild winter, Carter said.
While it’s difficult to predict what the weather will be in the next few months, Carter is concerned about the potential of very hot summers in the years ahead.
Two years ago, a report from Purdue University showed that from the year 1915 through 2013, southern Indiana averaged about seven extremely hot days every year.
But the 2018 Indiana Climate Change Impacts Assessment states that number is likely to increase to between 38 to 51 annually by the middle of this century.
“In the future, we will need to think about new plants, due to climate change,” said Carter. “We will need to be thinking of planting trees that are going to be more flexible, so they are not affected by warmer weather.”
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For more information on the National Wildlife Control Operators Association (NWCOA), visit nwcoa.com.