Weather and Fire Behavior Influencing the 11-12 June 2013 Black Forest, Colorado (USA) Wildfire

The June 2013 Black Forest Fire, associated with several dry intrusions of upper-tropospheric to lower-stratospheric air, is examined based on operational weather outlooks, together with satellite water vapor imagery, and surface and mid- to upper-air observations. Due to a number of extreme climatological and meteorological conditions, Colorado had been intermittently troubled by explosively large, destructive wildfires - sometimes fatal - since 1994, particularly in the month of June. The 2013 wildfire season would be no exception, and actually set some Colorado wildfire records. One of the record-setting fires, due mainly to the number of structures burned, was the Black Forest Fire. From the perspective of a Wildland Fire Supervisor, this paper will focus on the fire weather preceding the fire start, and the fire weather and subsequent fire behavior of the Black Forest Fire between 11-12 June 2013. This fire began about 1300 MDT on 11 June 2013 in El Paso County, (east-central) Colorado (USA) at 7379' elevation. It would burn for 10 days before it was 100% controlled on 21 June 2013. The noteworthy fire weather and fire behavior day was Wednesday, 12 June when the fire “exploded … and burned to the east, north, and west” resulting in the most structures destroyed. It burned entirely within the municipal limits of Black Forest and the confines of El Paso County, Colorado in a predominately mixed Ponderosa Pine, Rocky Mountain Douglas Fir, and Gambel Oak fuel type, in fairly moderate, rolling terrain. The fire was unremarkable in the actual 14,280 acres (22.31 mi²; 57.8 km²) burned, but significant in that 486 homes were destroyed, 37 others were damaged, and two people were killed. Hence, it was labeled as “the most destructive fire in Colorado history” as it surpassed the 2012 Waldo Canyon Fire's former distinction with 360 homes destroyed.

Synoptic and mesoscale weather, as well as regional climatology for 9-12 June 2013, are discussed to augment and support the Critical Fire Weather designations established by the National Weather Service (NWS) for that period. Weather elements that will be further analyzed include humidity, Haines Index, wind, overnight temperatures, and drought conditions. Ensemble air parcel trajectories are also included to determine the origin(s) of the dry air intrusions.