As a girl who was born and raised in a warm and humid city in Southern China with a lot of rivers and lakes, “fire” is not a familiar word to me, let alone the word “wildfire”. Therefore, when I knew the task for this lab and searched for the information of the 2009 station fire of Los Angeles, I was quite shocked by the power of the wildfire. The fire was originally started by arson, and it took 94 million dollars to fight with the fire by September 15th.
In order to study this problem, I made a slope map of the station fire and I was expecting that the fire would spread faster on flat terrain. However, on the map, I find that the fire actually spread towards the region with high slope. In a series of simulation experiment, some simulations have shown that fires will be accelerated when they spread uphill (Linn, et al.). This phenomenon is actually caused by two facts. First, the the lower less dense air which is heated by the ground will shift to the upper side of the mountain which accelerate the fire. Second, flames on the up slope side are closer to the fuel, and they can receive more radiant heat. However, form the map we can see that the slope is not totally useless in slowing the fire. As we can see, the steep slope at the east side of the fire actually impeded the expansion of the fire.
Hazards of the forest wildfire can be really severe. In the station fire, 160,577 acres were burnt, 22 people were injured and two firefighters were killed (Inciweb)(Garrison, et al.). In fact, the station fire has been the largest fire in the history of LA County and the 10th largest wild land fire in California. The scar of the burnt area photographed by the satellite can clearly show the destruction by the fire. What’s more, since the forest itself is a very precious resource for us, the destruction is really a heavy loss, not to mention the great influence to the local ecosystem. The Carbon Dioxide polluted would be bad for the global climate and the ashes produced could decrease the quality of the air in significant measure.
Photo via NASA.gov
What surprises me much is not only the intensity of the wildfire, but also the rapid spread of the fire. As we can see on the map, the fire’s extent was not really big from the beginning of August 29th. However, the extent increased more than five-fold, and by September 2nd, the fire had covered a really large area in the forest. When we look at the pattern of the spread of the wildfire, we can see that the fire mostly expand to the north east direction. This made me wonder if the spread of the fire has some relation with the feature of the terrain?
In order to study this problem, I made a slope map of the station fire and I was expecting that the fire would spread faster on flat terrain. However, on the map, I find that the fire actually spread towards the region with high slope. In a series of simulation experiment, some simulations have shown that fires will be accelerated when they spread uphill (Linn, et al.). This phenomenon is actually caused by two facts. First, the the lower less dense air which is heated by the ground will shift to the upper side of the mountain which accelerate the fire. Second, flames on the up slope side are closer to the fuel, and they can receive more radiant heat. However, form the map we can see that the slope is not totally useless in slowing the fire. As we can see, the steep slope at the east side of the fire actually impeded the expansion of the fire.
Another reason for the pattern of the spread of the fire is probably the land use. In the reference map, we can see that there are only few big blocks in the firing area while the blocks in the southern part are smaller and more concentrated. On the shaded model map, we can see that the fire range covered a Since the flat terrain is more suitable for people to live and the natural vegetation was cut off in order to make more living room, the area has become a natural fire compartment which could slow and stop the expansion of the fire. Since the spread of the fire is highly related to the vegetation, it is not hard to conjecture why the station fire would expand to the northern part.
This lab is another chance for me to see how useful GIS could be . When facing a natural disaster like a wildfire, GIS may seem not to be able to do something directly to help control the situation. However, it can effectively evaluate the impact of the disaster and help us make strategies about how to deal with the situation. Moreover, after the disaster, we can use GIS to make a good plan of post-disaster reconstruction. However, GIS itself can not do anything, and we need to well use our brains so we can use this effective tool in the best way.
This lab is another chance for me to see how useful GIS could be . When facing a natural disaster like a wildfire, GIS may seem not to be able to do something directly to help control the situation. However, it can effectively evaluate the impact of the disaster and help us make strategies about how to deal with the situation. Moreover, after the disaster, we can use GIS to make a good plan of post-disaster reconstruction. However, GIS itself can not do anything, and we need to well use our brains so we can use this effective tool in the best way.
Works Cited
O’Connor, Anahad, “Los Angeles Fire Was Arson, Officials Say.” The New York Times, 4 Sept. 2009. Web. 21 Mar. 2013
Station Fire Update Sept. 27, 2009. InciWeb. Web. 21 Mar. 2013
Garrison,Jessica, Alexandra Zavis and Joe Mozingo. “Station fire claims 18 homes and two firefighters.” Los Angeles Times, 31 Aug. 2009. Web. 21 Mar. 2013
"20 Largest California Wildland Fires (By Acreage Burned)". California Department of Forestry and Fire Protection. 3 Sept. 2009. Web. 21 Mar. 2013
Linn, Rodman R., Judith L. Winterkamp, David R. Weise and Carleton Edminster. “A numerical study of slope and fuel structure effects on coupled wildlife behavior.” International Journal of Wildlife Fire 19 (2010) : 179-201. Web. 21 Mar. 2013
“Topography’s Effect on Fire Behavior.” Auburn University
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