This week's lab allowed me to implement GIS in my analysis of the LA station fire of 2009. I created the reference map out of a map of LA county. I then added a DEM that represented elevation as well as data about major highways and the fire perimeter at different times. My thematic map depicts the level of fire threat in the area, with the station fire being in an area with high fire threat. As can be seen from both maps, the fire started out small (yellow outline) and grew incredibly large (black outline). A number of different factors contributed to the huge growth of this fire.
First of all, weather is a major factor in the spread of wildfires. During the time of the fire, the area was experiencing high temperatures, and very low humidity. This helped to create a very dry environment. Therefore, the grass and vegetation had little to no moisture content, thereby acting as an exceptional fuel source for the fire. Fires also spread faster if their fuel source is more dense or closer together, and this was the case in the Angeles National Forest. According to the USDA, the forest is densely packed with chaparral, pine, and fir.
Usually, wind is a big factor in the spread of wildfires, however it did not play a big role in the station fire. Moderate winds were present during the fire, but the driving force of the spread of the fire was elevation, primarily slope. Steepness of slope increases the spread of fires due to things such as heat rising due to convection, fire being closer to fuel sources, and wind currents pushing flames uphill. And, according to the DEM in the reference map, one can see that the wildfire is in an area of high, varying elevation. So, it is clear that slope and elevation played a major role in this fire.
The fire itself grew greatly and caused a great deal of damage. In only one night the fire was able to grow over 40,000 acres, doubling in size. In addition, over 12,000 homes were destroyed and over 6,000 people were evacuated. It was extremely difficult for firefighters to contain the fire due to the elements described above. The fact that wind was not a major force in this fire caught many firefighters off-guard. Overall, it took 52 days for the fire to be fully contained, and costed roughly $95.2 million.
This lab really summed up arc GIS. It shows in which circumstances it can be useful and how it can be used to represent data. The thematic and reference maps create a great visualization of the station fire. From both maps you can see the extent of the fire in relation to the county of LA, and observe how much the fire perimeter grew. Also, you can see some of the other elements that contributed to the fire, particularly slope and elevation. All of the elements that contributed to the spread of this fire are represented in the thematic map of fire threat, and we can now understand why the fire area had such a high fire threat. This ability of arc GIS to take data and create a snapshot of a real-world phenomena is truly its biggest potential.
Bibliography
"About the Forest." Angeles National Forest. USDA Forest Service, n.d. Web. 13 Dec. 2012.
Bonsor, Kevin. "How Wildfires Work." HowStuffWorks. Discovery, n.d. Web. 13 Dec. 2012. <http://science.howstuffworks.com/nature/natural-disasters/wildfire.htm>.
Garrison, Jessica, Alexandra Zavis, and Joe Mozingo. "Station Fire Claims 18 Homes and Two Firefighters." Los Angeles Times. Los Angeles Times, 31 Aug. 2009. Web. 13 Dec. 2012. <http://articles.latimes.com/2009/aug/31/local/me-fire31>.
Lloyd, Jonathan. "52 Days Later, Station Fire Is Contained." NBC Southern California. NBCUniversal, 19 Oct. 2009. Web. 13 Dec. 2012.
"Ministry of Forests and Range, Wildfire Management Branch." Fire Behaviour. British Columbia Forest Service, Wildfire Management Branch, n.d. Web. 13 Dec. 2012.
