NHERI-Affiliated Structural Extreme Event Reconnaissance Team Releases Report on December 2021 Tornado Outbreak

StEER provides detailed assessments and collected data on the NHERI DesignSafe Data Depot

Published on January 5, 2022


TO: NHERI users and the greater natural hazards community
FROM: Tracy Kijewski-Correa, Khalid Mosalam, David O. Prevatt, Ian Robertson, and David Roueche
RE: 10 December Tornado Outbreak

On December 29, StEER released its joint report for the 10 December Tornado Outbreak, available on NHERI DesignSafe Data Depot.

Representative streetview of residential buildings in downtown Mayfield, KY, Dec. 14, 2021. (Source: StEER)

In the late hours of 10 December and into the early hours of 11 December 2021, unseasonably warm air instigated an outbreak of at least 60 confirmed tornadoes across nine states. The outbreak included a family of damaging “Quad-State” tornadoes, with an EF4 tornado that was on the ground for over 160 miles, causing devastating impacts to many small communities and in particular Mayfield, KY. This tornado outbreak is expected to be one of the largest and deadliest tornado events in U.S. history.

Given the historic nature of this outbreak, StEER immediately issued a Level 3 response to this event, simultaneously activating its Virtual Assessment Structural Team (VAST) on 11 December, while its Field Assessment Structural Team (FAST) was assembled to begin collecting perishable data in Mayfield and surrounding areas on 14 December. StEER has released the first product of its response to this event: a joint Preliminary Virtual Reconnaissance Report-Early Access Reconnaissance Report (PVRR-EARR).

Importantly, this joint report underscores the need to design for tornadoes in high-exposure regions, a more realistic proposition given the recent release of ASCE 7-22 and its new tornado load provisions.

The FAST utilized rapid imagery capture methods to document accessible areas in Mayfield and other affected communities in Kentucky using a mixed methodological approach. As detailed in the PVRR-EARR, the collected data can be particularly advantageous in supporting future engineering investigations in the following topical areas:

  • TOPIC 1: Performance of essential and critical facilities
  • TOPIC 2: Safe room performance
  • TOPIC 3: Performance of critical infrastructure
  • TOPIC 4: Tilt-up structure performance
  • TOPIC 5: Storage silo performance
  • TOPIC 6: Recovery model development 

StEER also notes a number of topics in policy and practice that warrant further attention in the wake of these tornadoes:

  • TOPIC I: Promoting design for tornadoes
  • TOPIC II: Preservation of life safety in tornadoes
  • TOPIC III: Public response to tornado warnings
  • TOPIC IV:  Promotion of storm shelters

While these and other research topics are worthy of additional study, due to StEER’s mandate and the timing of clean-up relative to the approaching holidays, StEER does not anticipate deploying additional on-site FAST teams. The timing of this FAST was too soon to access some areas restricted by local authorities. Thus, StEER is eager to coordinate with other teams who decide to deploy, using RAPID funding or other funding sources, and strongly encourages them to make use of StEER’s archived data and where appropriate, share/coordinate their plans with StEER.

While data enrichment and quality control are ongoing, acquired data can be immediately accessed:

As always, we appreciate your collaboration in helping to Build Resilience through Reconnaissance. Please direct additional queries to admin@steer.network.

Best Wishes,

Tracy Kijewski-Correa Khalid Mosalam David O. Prevatt Ian Robertson David Roueche
StEER Director StEER Associate Director for Seismic Hazards StEER Associate Director for Wind Hazards StEER Associate Director for Coastal Hazards StEER Associate Director for Data Standards
University of Notre Dame University of California, Berkeley University of Florida University of Hawai'i at Manoa Auburn University


Project team members;

Pilkington, S. Roueche, D. Gutierrez Soto, M. Alam, M. Napolitano, R. Kijewski-Correa, T. Prevatt, D. Kaushal, S. Nakayama, J. Saleem, M. Ibrahim, H. Lyda, A. Lester, H. Caballero Russi, D. Gurley, K. Robertson, I. Lombardo, F. (2021) "StEER: 10 December 2021 Midwest Tornado Outbreak Joint Preliminary Virtual Reconnaissance Report and Early Access Reconnaissance Report (PVRR-EARR)", in StEER - 10 December 2021 Midwest Tornado Outbreak. DesignSafe-CIhttps://doi.org/10.17603/ds2-2b2k-ws96.