Detecting and interpreting wind damage at multiple scales in the 10 August 2020 Derecho using UAS, satellite, and radar

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 (UAS) 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 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.