Assessing topography and wind alignment for firefighter safety
William M. Jolly, US Forest Service, Missoula, MT; and J. Forthofer and B. W. Butler
Topography and winds are well-known contributors to wildland fire behavior. Taken individually, these factors are both important contributors to fire spread but when winds align with topography and blow directly uphill, fires can spread rapidly. These situations pose significant safety concerns for firefighters that might be caught on a slope with unburned fuel between themselves and an active wildfire. Here we demonstrate the applicability of a computational fluid dynamics model to map terrain-driven wind patterns and we show how these wind maps, combined with topographic information, can be used to classify areas where topography and winds align. We present a simple trigonometric model that can be used to characterize this relationship and map these areas of alignment and we use this method to illustrate the relationship between topography and wind in the 1994 South Canyon fire. This simple method can map topography and wind alignment a priori to improve firefighter situational awareness and safety.
Extended Abstract (204K)
Session 3, Improvements to Fire Danger and Fire Behavior Systems Related to Meteorology
Tuesday, 13 October 2009, 1:30 PM-3:00 PM, Lake McDonald/ Swift Current/ Hanging Gardens
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