Environmental Controls on Pyrocumulus Formation Using WRF-FIRE Simulations

Pyrocumulus clouds develop in a wildfire environment when thermals reach their level of condensation in the atmosphere. They have been linked to extreme weather events such as fire-induced tornadoes and rapid fire growth. Pyrocumulus also play a role in atmospheric chemistry, cloud microphysics, and smoke transport in the lower stratosphere. To better understand pyrocumulus formation, we use the Weather Research and Forecasting Fire model (WRF-FIRE) from the National Center for Atmospheric Research (NCAR). Building from a case of observed pyrocumulus cloud formation, we seek to assess the role of environmental variables. We use idealized simulations in WRF and vary ambient mixing ratio, inversion strength, and wind shear to delineate when pyrocumulus are likely to form.