Assessing the Potential for Pyroconvection and Wildfire Blow Ups

Abstract

Fire meteorologists have few tools for assessing atmospheric stability in the context of wildfires. Most tools at our disposal were developed for assessing thunderstorms and general convection, and so they ignore heat and moisture supplied by the wildfire. We propose a simple parcel-based model that can be used to assess how the atmosphere will affect a growing wildfire plume by also taking into account the heat and moisture released from the fire. From this model, we can infer trends in day to day atmospheric stability as it relates to fire plumes. We can also infer how significant the appearance of a pyrocumulus cloud on the top of a fire column is. In some cases, the appearance of a pyrocumulus indicates that the fire is near if not already blowing up, whereas in other cases environmental conditions remain too stable to have a significant effect. A qualitative application of the model is demonstrated through application to a 2017 wildfire case in Western Montana.