In the year of 2009, there was a Station Fire in Los Angeles County, in Los Angeles River Ranger District and Angeles National Forest. This fire started to burn on August 26 2009, and the fire is was fully contained on October16, 2009. In this incident, 2 fireman were killed, and up to 160,577 acres of land were burned. (Station Fire) From the Station fire Perimeter Map, we can see that the area of the fire on Aug30 was almost quadruple than the area of the fire on Aug29, and double the next day. In lab 7, the fire spreading patterns are studied, and i think the major factor that leads the fire spread this fast is due to the Elevation.
As well known, fire will continnus to combus when the three elements of fire triangle exists. Accroding to wikipedia, the three fire tirangle elements are heat, fuel, and oxidizing angent(such as oxygen) (Fire Triangle). Since the cause of this incident is because of arson(2009 fire summary), the require of heat is fulfilled; secondly, there are lot of woods in the angeles national forest, and they can used as fuel for burning; lastly, there was enough oxygen since the incident is occur in an open area. So, we can assume that the fire can continue burning until one of these three element used up. In this incident, the fuel may used up first because there is no rain and not enough man power to lower the heat, and the oxygen will not used up.
With the existing of fire trangle, we can futher analysis how the fire can be spread. According to Principle of Fire behavior, Fire seldom self-propagate (spread) through surface, so non-self-propagate(such as wind and Elevation) is the major reason that why fire spread. (P.84 Quintiere)The Defintion of flame spread is that process in which the perimeter of the fire grows. There are two major types of frame spread, assist and opposed frame spread(P.85 Quintiere ). In this incident, the fire is spreading from low land to high land, and this is one kind of upward spread (assist spread)(P.90 Quintiere ) . In the map, the green coloer means low land, and the brown color means high land. We can see that the fire perimeters were extended toward the brown color much more faster (assist frame spreading) than going to the green region (opposed frame spread).The spread rate can be calculated by a equation that stated in the book.
Aonther instersting point that I found out from the theme map is: the spread of fire is not much related to the rivers and stream, is that, the rivers and stream could not stop the spreading of the fire. We can see from the map; even though there is river or stream present, the fire will continue spread to the high land direction. I think the reason why the river cannot stop the spreading of the fire is that the river and stream may lower the heat, but the heat is still enough to combus with fuel and oxygen, and to propagate.
All in all, in this station fire incident, the fire spread from lowland to highland. The elevation is one of the major factors that plays an important role in this incident.
"Station Fire".Inci Web Incident Information System http://inciweb.org/incident/1856/. Nov 28, 2010 03:33
"Fire Triangle"http://en.wikipedia.org/wiki/Fire_triangle Wikipedia. Nov 28, 2010 03:33
"2009 fire summary" http://www.fire.ca.gov/downloads/redbooks/2009/02-wildland-statistic-all-agencies/11_2009_Fire_Summary.pdf California Department of Forestry and Fire Protection. Nov 28, 2010 03:33
Quintiere G. James. "Principle of fire behavior." Delmar, a division of Thomson learning.(1998 )
PS: This is the first time for me to use ArcGIS10, and I found out this new version is more easier to handle then the 9.3version :)
