Detecting and Interpreting Wind Damage at Multiple Scales in the 10 August 2020 Derecho Using UAS, Satellite, and Radar

Abstract On 10 August 2020, an intense mesoscale convective system (MCS) produced a derecho resulting in widespread high-wind damage from eastern Nebraska through northern Indiana with over 8200 damaged or destroyed houses and 11 billion USD in agricultural losses. Central Iowa, a predominantly agricultural area, was one of the hardest-hit areas due to smaller-scale rotational winds associated with mesovortices embedded within MCS-scale straight-line winds. This research aims to better characterize different types of wind flow and damage footprints of this derecho at multiple scales using multiple platforms and sensors [radar, satellite data, and uncrewed aerial systems (UASs) imagery]. Using vorticity detection algorithms and 88D radar data from Des Moines and Cedar Rapids, Iowa, mesovortices embedded within MCS-scale flow were identified and tracked. Satellite-derived products were used to capture the spatial extent of high-wind damage at the meso- β (20–200 km) scale, while high-resolution UAS data were used to distinguish types of high-wind impacts and characterize pockets of heavier damage down to the micro- β to micro- γ (submeter) scale. Analysis of UAS imagery revealed the presence of four tornadoes associated with radar-indicated mesovortex tracks and detailed wind impacts not captured in satellite imagery. One of these tornadoes is examined in detail. Even with improved spatial resolution of UAS imagery, characterizing high-wind damage impacts can be affected by land-cover type. By linking convective-scale radar signatures to detailed damage information, new knowledge of high-end derechos can be generated and leveraged for more specific warnings and to better inform damage assessments. Significance Statement This paper examines a “high end” derecho using multiple platforms and sensors (i.e., satellite, radar, and UAS), illustrating the relationships between storm-scale features and damage footprints at the appropriate spatial scales. This research demonstrates that damage has fine-scale structures down to 10-m scales. Damage patterns related to swirling winds on the 10-m scales are more likely in areas where larger-scale (km) flow is rich in Doppler vorticity.