Wildfires and Santa Ana Fires: Which Will Burn Longest?

Of the many wildfires in the West, it appears that Southern California has two distinct types: those driven by fall Santa Ana winds and those that turn up in hot, dry summer conditions. The increase of specifically summer fires with climate change is extending the traditional "fire season," as scientists from three California universities and institutions recently noted in a paper published in the journal Environmental Research Letters.

The wildfire versions are approximately equal in terms of acreage covered, but the rip-roaring Santa Ana-driven fires tend to consume more developed areas and have cost 10 times as much in the period 1990 to 2009. For the study, researchers were sourcing NASA satellite data and fire records (decades of them) from the California Department of Forestry and Fire Protection and the U.S. Forest Service, according to a release. 

"This research is coming at the right time, considering that California and western areas of the United States are expected to face increased fire risk in the near term from the current multiyear drought," Yufang Jin, at UC Davis and co-leader of the study, said in a release. During the study, Jin worked as a researcher at the University of California, Irvine.

For certain, the Santa Ana fires are a different animal, churning up intensity in desert air after it is funneled through canyons and mountain passes. They are more intense in the short term than are summer fires, burning half the territory burned on Day 1 of the typical fire. One example is the Cedar Fire in San Diego, in 2003, as the release noted.

Summer fires not caused by the Santa Ana, though, burn in a more slow-and-steady way and take place far off in the mountains. They have hot temperatures and thrive on dry vegetation as fuel, said the release.

The study found that both types of Southern California fires would increase. However, there will be accelerated vulnerability to the non-Santa-Ana fires, as Alex Hall of UCLA noted in the release.

Essentially, the increase of summer, non-Santa-Ana fires will make the usual "fire season" start much earlier, as Hall said in the release. Firefighting agencies will likely need to prepare for the greater demand for resources, and might experience regional competition for use of them, according to the release.