Radar observations of fire-generated tornadic vortices

Large, high-intensity wildfires can generate their own extreme weather, including fire-generated thunderstorms (i.e., pyrocumulonimbus; pyroCb) and rare fire-tornados. My research aims to understand these phenomena using state-of-the-science radars and lidars, which can probe the internal dynamics of wildfire convective plumes. This talk will use these data to examine the plume, vortex, and fire dynamics during three recent cases with firegenerated tornadic vortices and associated PyroCb in California during the summer of 2020. These fires are the Loyalton, Creek, and Bear Fires. We will also place these observations in the context of laboratory-established plume dynamics, especially the dynamics of plumes in cross winds, to better understand distinct vortex morphologies including “embedded” and “shedding” vortices. Additional aspects of the talk will include the link between vortex and PyroCb evolution, and the impact of backing wind profiles on the vortex sense of rotation. Collectively these analyses help paint a clearer picture of how and when wildfires produce extreme weather, paving the way for nowcasting and warning for high-impact extreme fire behavior.