Wildfire Risk Analysis

Data:

Specific data was necessary to fully analyze wildfire risk analysis within the Los Angeles Mountains. I first acquired a digital elevation map from the USGS seamless server. This DEM included all of Los Angeles County. Next I utilized a free data portal within the California Forestry and Fire Protection services website to obtain a raster image and data table of vegetation within LA county. Finally, a simple station fire parameter shapefile was needed to specify location and overall area of interest. By reclassifying and combining my two, raster models I compromised a working risk analysis map of the area around the 2009 station fires.

Analysis:

            The first step in my analysis was obtaining and reclassifying terrain slope in respect to fire risk. To do this, I modified my slope map to contain only 5 categories of value ranging from 1-10. Low sloping areas received a low value (less likely to assist wildfire) while increasingly steep slopes received higher values. Overall, fire burns in an upward direction, steep slopes allow wildfires to spread much quicker creating a larger hazard. My next step was vegetation analysis. My approach was very similar to terrain slope. I utilized the reclassification tool to rank vegetation types according to their burning characteristics. To effectively achieve this, I used “WHR10NAME” category within the attribute table. This category specifies overall vegetation type, not just specific species. In my reclassification, shrub or chaparral contains the highest burn index and received a value of 10. Wetland, agriculture, desert and barren areas received low values. Overall this reclassification provided a ramping scale from 1-10 representing the fuel capacity of vegetation subtypes. At this point, my final analysis required me to combine these two reclassifications. Both slope reclass and vege reclass were in raster form. This allowed me to simply sum up new fuel indexes within the raster calculator. The output was a scale ranging from 2-20. The higher the value, the more likely the area will burn out of control. Within my calculations, I chose to weight vegetation and slope exactly the same. The final touch was activating the station fire parameters and utilizing this boundary as a reference location. It is very evident that this area contains very high fire hazard.