Climate Experts Say March Floods Fit With a Pattern of More Frequent Weather Extremes

May 20, 2019, 5:45 a.m. ·

The Platte River during flooding in March. (Photo by Allison Mollenkamp, NET News)

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Flooding in March broke records in many places across Nebraska. It’s also the second big flood in the last ten years. That’s left some people wondering: did climate change play a role?

Flooding earlier this year was caused, in the short-term, by three big things. There was a lot of snow on the ground, warm rain melted the snow, and cold temperatures meant the ground was too frozen for water to soak in.

Steve Hu is a professor in the School of Natural Resources at UNL. He says weather leading into the flood had been unusual.

“So in January and February we had had record snowfall in this region, and on top of that record snowfall, we also had below average temperatures over those months,” Hu said.

While this year had more snow and colder temperatures, Hu says climate change isn’t making the winters snowier.

“Looking at the record, historical record, past 100 years, we don’t see a trend of increasing winter precipitation, so it’s just one event, and this event is particularly interesting because of the timing of the cold temperature and snowfall and follow-up precipitation,” Hu said.

Hu says events like this happening in short succession has to do with atmospheric circulation. And climate change means it’s more likely we’ll see different weather events at the same time.

“The circulation of the atmosphere favors certain kind of event to happen at such a timing, when one event happens then followed immediately by some different events. Their super-imposed effect is going to be much bigger, much impactful, than individual events,” Hu said.

Another way climate change can contribute to weather events like the March flooding is by making extreme weather more frequent.

Martha Shulski is Nebraska’s state climatologist and an associate professor in UNL’s school of natural resources. She says Nebraska weather’s tendency to change quickly is likely to increase.

“All the projections point to increased in variability, which, in Nebraska we already experience a lot of variability from year to year. We can go from the flood of 2011 to the drought of 2012 in a short period of time, and that’s only going to increase overall in a warmer world, and the occurrence of extreme events, we can expect those to be enhanced in a warmer world as well,” Shulski said.

Shulski also says while the winters may not get snowier, the type of rain that contributed to flooding this year is likely to keep happening.

“We should prepare for and expect more things like this in a warmer world. If you look historically we’ve gotten wetter over time during spring and that’s a trend that is expected to continue, so winters and springs overall are going to be wetter than they are now in an overall warmer world. So things like this, I think, are going to be happening more so in the future,” Shulski said.

The need to prepare goes beyond just rainfall. David Pearson is Service Hydrologist for the National Weather Service in Valley, Nebraska.

“I think if you’re vulnerable to living in an area that can flood frequently, taking precautions to mitigate that the best you can, whether that’s buying flood insurance, putting up protective measures if you can, because in some cases the flooding could happen more easily, but the other side of the coin to that is dryness, being ready for drought if you’re susceptible to that as well, because the extremes could happen on either end,” Pearson said.

Shulski says that chance of extreme drought, and overall climate trends, could be bad news for agriculture.

“One thing I think about is increase in extreme heat during the summertime, and what if that happens during corn pollination when the plant is really vulnerable to that? Summers are likely to get warmer with more extreme heat and drier, so the combination of those things speaks to the plants will need to use more water,” Shulski said.

Hu has some advice for farmers and other Nebraskans as they prepare for the effects of climate change.

“We should pay attention to the science or to understand, pay attention to whatever information we are provided by professionals, by research communities, and then we learn in the process to help us understand,” Hu said.

Predicting climate and weather is a complex science, But Hu believes we have to pay attention, because climate change is coming.

“Change is inevitable, so the best way to deal with change is would be to be prepared,” Hu said.

As Nebraskans recover from past flooding, they will also have to consider the possibilities that come with climate change in the future.