Research: Multi-disciplinary investigation of concurrent tornadoes and flash floods in the Southeastern US

Our research group has been involved in several projects related to the VORTEX-SE initiative. These have focused on the problem of concurrent, co-located tornado and flash flood ("TORFF") hazards, which are especially common in the southeast US and with landfalling tropical cyclones. Over the course of these projects, this research has included collecting observations in the field, investigating the characteristics of storms that produce TORFF hazards with observations and models, working with social scientists to understand the challenges National Weather Service forecasters face when issuing warnings for these hazards, investigating TORFFs in landfalling tropical cyclones, and using Twitter data to understand perceptions of multi-hazard events. Much of this research was led by former student Erik Nielsen, in collaboration with Dr. Jen Henderson (now at Texas Tech University).

Near-real-time monitoring of TORFF overlapping warnings can be found at: http://schumacher.atmos.colostate.edu/weather/TORFF_rt/ Our work on TORFFs has been incorporated into training materials for NWS forecasters.

Papers related to VORTEX-SE projects and TORFFs:

• Nielsen, E.R., G.R. Herman, R.C. Tournay, J.M. Peters, and R.S. Schumacher, 2015: Double Impact: When both tornadoes and flash floods threaten the same place at the same time. Weather and Forecasting, 30, 1673-1693.
• Nielsen, E.R., G.R. Herman, R.C. Tournay, J.M. Peters, and R.S. Schumacher, 2016: Reply to "Comments on 'Double Impact: When both tornadoes and flash floods threaten the same place at the same time.'" Weather and Forecasting, 31, 1723-1727.
• Nielsen, E.R., and R.S. Schumacher, 2018: Dynamical insights into extreme short-term precipitation associated with supercells and mesovortices. Journal of the Atmospheric Sciences, 75, 2893-3009.
• Nielsen, E.R., and R.S. Schumacher, 2020: Dynamical mechanisms supporting extreme rainfall accumulations in the Houston "Tax Day" 2016 flood. Monthly Weather Review, 148, 83-109.
• Nielsen, E.R., and R.S. Schumacher, 2020: Observations of extreme short-term precipitation associated with supercells and mesovortices. Monthly Weather Review, 148, 159-182.
• Henderson, J., E.R. Nielsen, G.R. Herman, and R.S. Schumacher, 2020: A hazard multiple: Overlapping tornado and flash flood warnings in a National Weather Service Forecast Office in the Southeastern United States.Weather and Forecasting, 35, 1459-1481.