UNL Drought Risk Atlas Helps Reveal the History of Drought

The Drought Risk Atlas provides drought data and visualizations for more than 3,000 climate stations across the U.S. through 2012 for at least 40 and in some cases more than 100 years. (Credit: National Drought Mitigation Center)
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April 2, 2014 - 6:30am

This week the University of Nebraska-Lincoln hosts the 40th Annual Great Plains Symposium: Drought in the Life, Cultures and Landscapes of the Great Plains. To preview the symposium, NET News spoke with Mark Svoboda, climatologist with the National Drought Mitigation Center at University of Nebraska-Lincoln, about current drought conditions in the state and a new tool recently launched to help decision-makers and the public better understand and prepare for future drought.


NET NEWS: Bring us up to date on drought conditions in Nebraska.

MARK SVOBODA: In Nebraska it’s really been a mixed tale: very beneficial moisture in the western part of the state, particularly the Panhandle, and parts of north-central Nebraska in the Sandhills region. As you move east and south, southwest Nebraska is still taking the brunt of it, experiencing a multi-year drought, low soil moisture reserves, low surface water supply, impacts to groundwater levels, etc. As you come into the eastern part of the state, it was a really cold, dry winter and the snows we did get were below normal and very dry, so they didn’t contain a lot of water. And a lot of that snow blew all over the place so it wasn’t very beneficial.

The U.S. Drought Monitor releases weekly reports on drought conditions across the country. You can find more here.

NET NEWS: Nebraska and other Plains states continue to experience moderate to extreme drought. How have we seen that play out in terms of impacts in recent years?

SVOBODA: Again, that part of the state [southwest], it’s somewhat spotty but in general, it’s been impacted for almost three years. Once you’re in a drought that long, it doesn’t just recover overnight. Even if they got heavy rain, a lot of that isn’t going to work its way into the groundwater until the soils are saturated. And they’re so dry right now, down to several feet in some cases, that it’s going to take a more gradual recovery to be very effective.

NET NEWS: The Rockies have been getting a lot of moisture this winter. How does the water supply look this year in Nebraska?

SVOBODA: That’s the silver lining. Compared to the last two years, when the Rockies had seen really low snowpack, this winter they’ve had a great abundance of snowpack, anywhere from 105 to 190 percent of normal or more for some of the basins that feed the Platte River. From a surface water supply standpoint, it looks like we’re starting to fill up some of those reservoirs upstream in Wyoming and Colorado. And the fact that the big flood in Colorado knocked out some of the dams and water diversions means even more will flow into Nebraska this coming spring. We’d like to see that melt out slowly so we can see more snowmelt make its way into the Platte system. So from that standpoint it looks pretty good, but the Republican River Basin in the southwest part of the state isn’t quite as good. They didn’t get a lot of snow there so that’s still a concern.

NET NEWS: The National Drought Mitigation Center here at UNL has launched a new resource called the Drought Risk Atlas. Can you explain what it is and what it’s going to be used for?

SVOBODA: One of the questions we always get from the newspapers and radio and TV and people in general is, how does this drought compare to the Dust Bowl years, or the 70s, or '88? Everyone seems to have a drought they remember. The Drought Risk Atlas was built with the idea that for the best climate stations out there that have really nice, long-term histories, not a lot of missing data, we can go back and look at the drought history. We’ve built a nice visual interface to that. People that want to download the raw data can get it, but it’s also a nice way to come in and look at the spatial behavior of drought, the intensity of drought. How large of an area, how long did it last, how often does that sort of drought come around? That was the motivation in building this tool, to help decision makers, citizens, and the media. We’re going to generate more than 500,000 maps of drought for each week of every year back to the early 1900s.

NET NEWS: Why is this needed or useful?

SVOBODA: It’s to give people a better sense of how they  might need to adapt, preparing to get a different mindset about droughts, that they’re a normal part of our climate. We’ve seen [droughts] in the past and we’ll see them in the future with a changing climate. Are these droughts changing in their frequency? Are we seeing them become more intense but more short-lived, are they long-lived but of just a moderate intensity? Knowing how that impacts you and your operation, whether you’re a farmer or rancher or whoever it might be, may help us look out to what we should expect from droughts in the future.  

NET NEWS: Will the Drought Risk Atlas help predict drought and prepare for drought in the future, knowing the historical record?

SVOBODA: Where I think this tool will be useful is if you see a forecast for drought, or if you’re in a certain stage of drought, you can go back in the Atlas and look at other periods of drought that behaved the same way and maybe you’ll have a better anticipation of what might be coming.  If this drought continues, if it gets more intense, if it covers a larger area, will this affect my water supply? Our goal was to provide some of the visualization tools that can answer more questions.

NET NEWS: Some irrigators in Nebraska have talked about the “new normal”—meaning they’re getting used to operating with less water year after year. Do you think the same concept applies to drought, in the sense that we’re in these longer phases of drought or maybe we’re entering a longer dry period?

SVOBODA: That’s the kicker question. The million dollar question is, is this an interlude? We may go back into wetter times. The models that the IPCC (Intergovernmental Panel on Climate Change) released in its report still show the continuing trend of a hotter atmosphere, which exacerbates drought, but also a moister atmosphere. So it depends on the timing of these rains, how many days in-between these rains. But in general, it’s not as easy as it was to look at the past and say, the climate of the past is going to equal the climate of the future. The bars have changed. And if that shift continues long enough, say a couple decades, that would mean more of a climate shift to the climate regime of a region. We would call that more arid, or aridity, which is a permanent feature of the climate, versus drought which is a temporary departure from the normal of a region’s climate. So droughts are going to then be the departure from that new, drier regime.

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