Over the past two weeks, numerous wildfires have ignited across the state of California. High pressure, dry conditions, and a special flow pattern in Southern California called the Santa Ana Winds have helped to drive one of the largest recorded wildfires in state history, the Thomas Wildfire. The fire has ravaged over 267,000 acres over its two week lifespan, and the outlook does not look promising.
Setup and Ignition
The Thomas Fire began on Saturday December 4th, due to moderate drought and the Santa Ana winds. Santa Ana winds form from cool and dry high pressure systems over the southeastern United States. As the dry winds push towards the west coast, they are effected in two ways. The first is that they are funneled between the coastal mountains in the southern half of the state. Funneling the winds helps to increase the wind speeds as they travel down the slopes, which is the second way the winds are effected. Air that is forced to sink will compress, warm, and dry even further.
The net result, strong and dry winds were funneled into an already dry region. Meaning Southern California Coast had the idea conditions for large, dangerous, and fast moving wildfires. All it needed was a spark.
Spread and Impacts
Enter stage right the Thomas Fire, which quickly spread in size. Its speed prompted numerous evacuations of local communities, and over 1,200 structures destroyed or damaged by the fires. So far, estimates place the damage at over $96 million. Unfortunately, one civilian and one San Diego firefighter have lost their lives to the fire as well. A veritable army of personnel have been on site, fighting the dangerous fire, and have reached 40% containment as of Saturday evening.
While many are wishing that the ending was in sight, this unfortunately is not the case. Winds have continued to gust over 50 mph over the area, pushing the fire southward, and prompting several more evacuations to more threatened communities.
“Critical fire weather will continue over the fire area, with north/northeast winds forecasted. This weather pattern will be conducive to west- and southward fire growth, continuing to threaten the communities of Santa Barbara, Montecito and Summerland in Santa Barbara County.” -California Department of Forestry and Fire Protection