Other Instabilities » MAULs Moist Absolutely Unstable Layers (MAULs)
Bryan and Fritsch (2000) posed that saturated layers may exist in the lower to middle troposphere that have lapse rates that exceed the moist-adiabatic lapse rate and are therefore moist absolutely unstable layers (MAULs). A MAUL may be better understood by considering the evolution of the sounding in this animation. The initially unsaturated 900-600 hPa layer is lifted 100 hPa and becomes saturated. The resulting lapse rate of the saturated 800-500 hPa layer is steeper than the moist-adiabatic lapse rate, hence the formation of a MAUL.