Wildfire

The 2011 fire season was record-setting, with more than 1 million acres burning in Arizona and New Mexico between January 1 and September 30. The groundwork for a devastating fire season was laid last winter when a moderate to strong La Niña event helped push storm tracks north of the Southwest. The dry conditions desiccated soils and live fuels such as grasses, shrubs, and trees by the spring. A cold snap in February also contributed to the build-up of fuels because the hard freezes killed many plants. In the spring and summer, the dry conditions combined with persistently strong winds to amplify the fire risk and inhibit efforts to quell wildfires.

In part because of the La Niña event, Predictive Services at the Southwest Geographic Area Coordination Center correctly forecasted above-normal significant fire potential across most of the region. Southeast New Mexico and southwest Arizona experienced the most fire activity (Figures 5a–b). Approximately 1.1 million acres burned in New Mexico this year, more than 4.5 times the state’s average of approximately 242,000 acres (Figure 5c). In Arizona, slightly more than 1 million acres burned, more than 5.5 times the state average of approximately 182,000 acres (Figure 5c).

In Arizona, almost half of the damage was caused by the Wallow Fire, which began on May 29 in the White Mountains. The blaze consumed more than 538,000 acres spanning Apache, Navajo, Graham, and Greenlee counties in Arizona and Catron County in New Mexico. It replaced the Rodeo-Chediski Fire, which burned almost 470,000 acres in 2002, as Arizona’s largest wildfire on record. The onset of the monsoon occurred around its historical onset date in early July, helping firefighters control many other large fires and reducing the number of new fire starts.
 

Click figures to enlarge.

Table 4. Ten Largest Southwest fires in 2011.

Fire Name	State	Acres Burned
Wallow	AZ & NM	538,049
Horshoe 2	AZ	222,954
Las Conchas	NM	156,593
Donaldson	NM	101,563
Miller	NM	88,835
Murphy Complex	AZ	68,079
Enterprise	NM	64,936
Last Chance	NM	53,342
Baton Rouge Complex	NM	35,165
Windy	NM	32,437