Tuesday, 5 May 2015: 4:00 PM
Great Lakes Ballroom (Crowne Plaza Minneapolis Northstar)
The King Fire was started by arson on 13 September 2014 in the Sierra Nevada foothills near the town of Pollock Pines, CA. The fire escaped initial attack and began making significant runs on 15 September necessitating a fire-shelter deployment for a suppression crew. By the morning of 17 September, the fire had burned about 20,000 ac and damaged or destroyed numerous structures. During the following evening the growth rate drastically increased with the fire consuming an additional 50,000 ac overnight. In this presentation we use in situ and remote observations to examine the boundary layer and synoptic-scale meteorology driving this critical transition in fire growth. On 15-17 September, observations of the King Fire convective plume and boundary layer evolution were made using a truck mounted scanning Doppler lidar, microwave temperature profiler, upper-air radiosonde system, and surface weather station. Additional satellite, RAWS, and model data help to contextualize these observations. Preliminary results show typical diurnal transitions in the coupled fire and boundary layer evolution on the 15th through early on the 17th. These observations include high-resolution lidar scans of plume dynamics during the morning and evening transition periods. In contrast, on the afternoon of the 17th strong synoptically driven southwest winds mixed to the surface. These winds contributed to strongly tilted convective plumes and disrupted the typical evening transition leading to extreme nocturnal fire behavior, long distance spotting, and rapid fire growth.
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