An Assessment of the Extremes and Impacts of the February 2021 South-Central U.S. Arctic Outbreak, and How Climate Services Can Help

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Investigator(s): John Nielson-Gammon, Crystal Stiles, William Tollefson, Hannah Attard, Vincent Brown, Alicia Bentley, Barry Keim, Becky Bolinger, Christopher Fuhrmann, Karin Gleason, Andrew Joyner, Amanda Lewis
Research Dates: 2021 - 2022
Affiliate Organization(s): Louisiana State University • Texas A&M University • National Centers for Environmental Information • Colorado State University • Mississippi State University • East Tennesse State University • Cooperative Institute for Research in Environmental Sciences • University at Albany, State University of New York

In February 2021, a widespread cold-air outbreak, with two associated winter storm systems, impacted the South-Central United States. After a comprehensive summary of the synoptic setup and a day-by-day analysis of the event, we assess the significance of the storm from a climatological perspective. Concerning winter precipitation, there were isolated instances of record snowfall accumulations. While freezing rain and freezing drizzle both occurred, total freezing precipitation accumulations did not exceed a one-in-50 year event. The duration of the cold was notable — many stations across the region broke records for the highest number of consecutive days below freezing. When analyzing hourly temperature observations, we found that the February 2021 event was the record longest duration of hours below freezing for 12 stations. Nearly 6,000 daily temperature records were broken by this event. We next summarize significant impacts of this event. While we find that this event was extreme, most aspects of this storm were not unprecedented. Even in the context of a warming climate, cold events such as this should be considered when assessing risk and hazard mitigation planning. The magnitude of impacts associated with this event suggests a lack of preparedness that needs to be addressed. We discuss the importance of using climate services in planning for future extreme events. While there are documented benefits to users engaging with climate service providers and integrating climate information into their decision-making, the February 2021 event serves as an example of the failures that can occur when climate services have not been integrated into planning. We recommend the use of climate services when assessing risk and planning for future climate and weather extremes.

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