Lab 6- Corey Rovzar

ArcGIS Tutorial





























Fire Hazard Map



















Write-Up

In order to create the fire hazard model for the Station Fire, it was first necessary to do some background reading on the fire in order to allow for a basic understanding of the area. Important information that I ascertained was that the Station Fire occurred during the late summer of 2009 north of Los Angeles in the Angeles National Forest and was one of the largest wildfires of summer 2009 (http://www.cnn.com/2009/US/08/31/california.wildfires/index.html). The next step in the process was to find perimeter, elevation, vegetation, fuel rank, as well as any supplemental data in order to perform the analysis. Although I was able to find data for the Station Fire relatively quickly, it was difficult for me to decide what to include. The California Department of Forestry and Wildfires provides many different shapefiles concerning California wildfires. It was difficult for me to assess which data were important and relevant, and which were not. In the end, I decided that ultimately the perimeter, vegetation type, and digital elevation data were the most important to depict in my fire hazard map. Understanding the type of vegetation and the slope of the land, allowed for an analysis of fire susceptibility. Additionally I felt that including a small map showing the fuel rank of the land cover would also be useful in understanding the potential for fires. Although there was more data concerning surface fuels and other fire hazards, I wanted to overall highlight the effect that vegetation type has on propagation of fires.

After collecting the data needed, I began my analysis. The first step was to select the Station Fire perimeter from the shapefile containing all the California wildfire perimenters, and create a new layer. Using the Station Fire perimeter layer, the raster images of the digital elevation model, vegetation type, and fuel rank shapefiles were clipped. Clipping the raster images was a difficult process that required transformations and adjusting the settings for the raster images. A hillshade was created for the clipped digital elevation model, and was then overlayed with the vegetation type layer in order to display a slope-vegetation map of the Station Fire. Hydrological Tigerline data from the US Census website was also added to the map in order to show the location of various creeks. Other Tigerline data including major roads and areas of interest were going to be added, however, I found that there were few major roads and areas of interest within the Station Fire Boundary. Most of the area was encompassed by the Angeles National Forest. After performing a slope-vegetation analysis, an additional map showing the fuel-rank for the land cover of the Station Fire was created. The categories of Non-fuel, moderate, high, and very high were ascribed to the different levels of flammability for the land cover. The final stages of the analysis included adding an inset window to show where the Station Fire occurred as well as including map elements (scale bar, title, north arrow, etc.).

Overall, the main purpose of my fire hazard map was to facilitate understanding as to possible factors that perpetuated the Station Fire as well as the potential for another fire to occur in this area. By evaluating the slope-vegetation map, it is clear that most of the area is covered by shrub at moderate elevation. By then comparing this map to the fuel-rank map, it is evident that the area covered by shrub correlates with a very high ranking as fuel for fires. Therefore, a potential theory for the intensity of the Station Fire could be that it originated in an area that contained high levels of vegetation that was extremely flammable. Understanding the underlying factors that may have contributed to the intensity of the Station Fire allows for greater awareness of fire potential in areas with the same conditions.