Preliminary meteorological analyses of the 2011 ‘Texas Firestorms'

In recent years, episodic drought has contributed to the occurrence of extreme and destructive wind-driven grassland wildfire outbreaks across the Southern Plains. The Texas Forest Service has stated that the most violent wildfire outbreaks are “a perfect storm for extreme fire…natural disasters that are truly beyond our capability to do anything about”, and has termed such events that impact the state as ‘Texas firestorms'. This study provides preliminary meteorological analyses of three ‘Texas firestorms' that occurred on 27 February, 9-10 April and 14-15 April during the severe to exceptional drought of 2011. These analyses are compared to a previously documented meteorological composite that relates Southern Plains wildfire outbreaks to the passage of mid latitude cyclones. While the evolution of the 27 February wildfire outbreak closely resembled the synoptic scale composite of similar past events, the 9-10 April and 14-15 April ‘firestorms' deviated from conceptual models. During those events, prolonged ‘firestorm' conditions persisted as favorable wind, humidity and fuels additionally occurred in association with 1) the initial infringement of strong wind fields upon low-level thermal ridging in advance of the approaching cyclone and 2) within the post frontal environment immediately following the cyclone. Through documentation of the latter ‘Texas firestorms', this study expands conceptual models for Southern Plains wildfire outbreaks to include the potential for multi-day episodes prior to, during, and in the wake of passing mid latitude cyclones, especially during periods of unusually dense and dry fuels.