National Drought Mitigation Center


U.S. Drought Monitor now offers tables showing drought impacts at state level

September 26, 2019

National Drought Mitigation Center research assistant Mary Noel recently presented on the creation of the state impact tables for the U.S. Drought Monitor at the USDM Forum in Bowling Green, Kentucky.

Over its 20-year evolution, the U.S. Drought Monitor has provided a weekly summary of drought conditions across the country and, over time, all of the U.S. territories as well. With each dispatch, the USDM points out areas that are experiencing varying categories of drought, from abnormal dryness (D0) to exceptional drought (D4). Along with the map, the USDM has offered a table of what impact those different levels of drought can cause across a landscape, from slow pasture growth in D0 to widespread crop loss in D4.

But drought looks different across the country’s nearly 3.8 million-square mile span, which the National Drought Mitigation Center captures with a new set of USDM tables that reflect drought impacts at state levels. The project, led by NDMC research assistant Mary Noel, provides localized drought impact tables for all 50 states and Puerto Rico and is now available to the public on the USDM website.

“It really supports all the pillars of drought planning,” said Noel, who recently graduated with a master’s degree from University of Nebraska-Lincoln School of Natural Resources. “It connects the impacts and assessments to monitoring pillars. It connects impacts to mitigation. If you don't know what's actually occurring in that state, then how do you know what to plan for and how to help out?”

The tables offer information that includes the often-considered agricultural impacts of drought, while also listing key impacts outside of that realm. In severe drought (D2), house foundations in Alabama may crack, Connecticut golf courses begin to conserve water and dust storms may sweep across New Mexico. In extreme drought (D3), the health of Nevada’s wild horse population is likely to deteriorate, leading officials to round up and relocate them to less impacted areas.

“They're all unique, which is a great outcome,” Noel said of the tables. “We really wanted these tables to bring awareness to these underrepresented sectors that are affected by drought. The goal is twofold. One goal is for the users of the U.S. Drought Monitor to understand what this level of severity actually means for their area. The other is for the USDM authors to help them better understand what category of drought they should label a place. So it's both the users and the authors who can utilize these tables.”

The localization effort, which was Noel’s master’s research project, won first place for poster presentation at the American Meteorological Society’s 2019 annual meeting. Noel recently presented on the project at the U.S. Drought Monitor Forum in Bowling Green, Kentucky, one day after the tables debuted on the USDM website. Noel said session attendees approached her afterwards with numerous questions, many centered upon the prospect of expanding upon the research in their own disciplines.

That’s been the plan all along, she said, since NDMC director Mark Svoboda and monitoring coordinator/USDM author Brian Fuchs discussed the idea of creating state-specific tables with her after she enrolled in graduate school in her hometown. Noel graduated with a bachelor’s degree in earth sciences from California Polytechnic State University-San Luis Obispo in 2017, spending her undergraduate years in a state that experienced drought the entire time she lived there.

To create the state impact tables, Noel focused on one drought event in each state, gathering information from entries in the Drought Impact Reporter, a database created in 2005 to collect on-the-ground reports about emerging droughts. DIR impacts reported during the onset of the selected drought events were downloaded, coded and cross-referenced with the USDM’s drought severity levels at the time the impacts were reported. Beginning the sizable undertaking alphabetically, Alabama was the project’s pilot state.

“We linked from the U.S. Drought Monitor to the impacts so you knew dryland farming stress happens at a D1 level in Alabama,” Noel said. “We analyzed all those impacts and the severity levels when they occurred, synthesized them together and formed a concise, easy-to-read and understandable list of impacts that occurred in Alabama for the different severity levels.”

Noel then fact-checked the tables with stakeholders in Alabama to confirm that the impacts found during data collection were accurate.

“Mary really embraced this idea that, if you could get feedback from the local stakeholders, it would enhance the tables even further than what she was doing herself,” said UNL School of Natural Resources climatologist Michael Hayes, one of Noel’s advisors on the project.

Noel said that 89 participants from 33 states and Puerto Rico provided vital “ground truthing” for the project.

Hayes said that the effort will help provide key context for residents of a state where drought is developing, as well as for non-residents whose notion of drought impact is based upon their experiences elsewhere.

“For instance, the state of Washington has had a drought event in 2019,” Hayes said. “Having a table tailored for Washington, or a table tailored for any other state that's having a drought event, is going to be much more relevant than a national overview table. If you can make a table more specific for where drought is actually occurring, I think that's where the benefit is. And it illustrates again that drought is going to be different where it occurs around the country. In theory, it'd be awesome to have tables for every county.”

While a set of county-level impacts might not happen in the near future -- there are more than 3,000 of them in the U.S., after all -- Noel said the state impact tables were released this month with the expectation that they will be updated and evolve.

“I'm really excited that this project was actually implemented,” she said. “People want to use it, and it can be used, which I think is the whole purpose of science.”

-- By Cory Matteson, NDMC Communications Specialist