lab 8

(the big picture) 

                                                                  ( the big picture )

This lab report is about the Los Angeles Station Fire that happened in summer 2009. I analyze the fire by using all GIS techniques I have learned in Geo7. In my lab report, I will focus on the direction of the fire. Thus, I try to find geographical factors that may affect the direction such as winds and highways nearby.

The LA station fire happened in summer 2009. This fire caused a lot of damage.  According to National Climatic Data Center, the station fire is the largest fire in LA history, and it “burned an estimated 160,577 acres.” In addition, it threatened nearly 12,000 structures, and 209 of them were destroyed in the fire (NCDC). Besides, due to the removal of vegetation in the fire, a lot of areas are now at the risk of “massive erosion, debris flows, and flooding during subsequent winter storm seasons and summer storm events” (Angeles National Forest). Until today, people in LA are now still be affected by the fire in a negative way. Thus, it is still important for us to analyze this fire.

First of all, let’s take a look at the picture above. It is the digital elevation model of L.A County station fire. In the picture, the LA County is bounded in green line, and fires on different dates are in different colors. The darker the color is, the newer the fire is. For example, the fire on 09/02 has the darkest color while fire on 08/29 has the lightest one.   

From the picture, I figure out that the fire spread quickly to the northwest in the first day and spread quickly to the east and west in the next day. And finally spread to the east.  Most people may have 2 questions now.

1.     How can the fire spread so quickly?

2.     Why can change the direction of the fire？

 The answer to the first question can be the wind. There is one kind of wind called Santa Ana Wind. It is a strong, extremely dry and hot wind that can be a nightmare for firefighters(Hall par.4). Mark Beighley and Jim Bishop, in their article “Fire Behavior in High-Elevation Timber,” proved this point. According to them, “Fire spread rates and intensities were extremely sensitive to small variations in fire environmental factors, with quantum steps up or down in spread rate and intensity from small changes of relative humidity of wind” (23) Under the effect of “Santa Ana Wind,” the Station fire spread quickly.

To answer the 2^nd question, I set up a hypothesis that the highways will influence the spread of the fire after a little research. To test my hypothesis, I make the thematic map that contains both the fire-spread patterns and the highways near the firing region. The theme map only focus on the fire region.

Let’s take a look at the thematic map below.  It is a picture about the major highways near the fire in 2009. In the picture, it seems that the fire stopped in front of the highways. Only one highway went cross the fire area, and the fire started near the highways and went into the opposite direction. The explanation for this phenomenon may be complicated. My guess is that near highways there is less vegetation that can support combustion. Thus, the fire “stopped” in front of the highways since highways separated the fuel and the fire.

In the end, the fire was contained. However, it has brought countless loss for all people in LA. By using GIS, I have a deeper understanding of this tragedy. I hope more people can have the chance to know the information, so we can try our best to avoid major fires in the future.

Works Cited

Angeles National Forest. Station Fire Restoration Fact Sheet. 15 April.2011. Web. 21 Mar. 2013.

http://www.fs.usda.gov/detail/angeles/home/?cid=stelprdb5313129

Beighley, Mark, and Jim Bishop. “Fire Behavior in High-Elevation Timber.” Fire Management Notes. 2 Feb. 1990. Web. 21 March 2013.

http://www.fs.fed.us/fire/fmt/fmt_pdfs/051_02.pdf

Hall, Carla. “Santa Ana winds now a threat in the Station fire.”  LA Times.22 Sep.2009. Web. 21 March. 2013.

http://articles.latimes.com/2009/sep/22/local/me-fire-danger22

National Climatic Data Center (NCDC). Wildfires Annual 2009. 8 Jan. 2010. Web. 21 Mar. 2013.

http://www.ncdc.noaa.gov/sotc/fire/2009/13

The Big Picture. “Wildfires in Southern California.” boston.com. The Boston Globe, 2 Sept. 2009. Web. 4 June 2011. 

http://www.boston.com/bigpicture/2009/09/wildfires_in_southern_californ.html


others:

http://gis.ats.ucla.edu/

UCLA GIS Data archive

http://egis3.lacounty.gov/dataportal/?tag=lar-iac 

LA County GIS Data Portal

lab 7

The first map is the distribution of Black people in the United States. The darker color indicates a higher percentage of Black population while the lighter ones indicate a smaller percentage of Black population. As we can see from the map, there are much more black people in southern part of the U.S than in the north. Some states have black people ratio up to 86%. The reason may be historical since we know that southern part used to be the place of slaveries.  

The 2^nd map is the distribution of Asian population in the United States. In my map, I divide Asians’ density into 6 levels. The darker red color indicates a higher percentage of Asian population. The lighter one indicates a lower percentage. From the map, we can see that Asian people like to live on the coasts, while in the central US there are fewer Asian people. One of the reasons may be the job opportunity. Since most of the large cities are on the coast, many Asians like to be there to get a job. For example, cities like NYC, SF, LA, the Asian population there are nearly 50%, which is really high.

The last one is the distribution of other race in the United States. The darker green color means a higher percentage of other race, while a lighter one means a lower percentage. In the map, from Texas to east coast, there is a high percentage of other race. I guess the reason is that most of these people are from mexico or South America  and states like Texas, California are closer to their countries . Thus, they will choose these states. However, the overall percentage of other race is not as high as black and Asian. The highest percentage is still less than 40%.

In conclusion, the three maps above show the population distribution in the US. In lab7, I find that census map can provide a lot of information about geography. We can use ArcGIS to analyze the map. ArcGIS is very useful and the maps we make is pretty straight forward. Even some people without much background can understand them well. After this lab, I am more familiar with ArcGIS and its functions right now.