AIR: conditions are worse this year because state experienced its driest spring since 1894

In northern and central California, firefighters have contained about 1,400 of the nearly 1,800 wildfires burning since June 20th, according to a report by catastrophe modeller AIR-Worldwide.

These fires—ignited by lightning and fuelled by conditions in the state's driest spring since 1894— continue to threaten some 10,500 homes and more than 400 commercial properties. They have burned close to 600,000 acres.

Firefighters are making some progress, AIR said. Yesterday, crews constructed a fire line on the eastern side of the Gap Fire, a particularly large and fast-moving inferno in the Los Padres National Forest. The Gap Fire expanded dramatically between Tuesday 1 July, and Wednesday 2 July, growing from 200 acres to more than 2,400. By Sunday, it had spread across 9,924 acres of California land and was only 30% contained.

It continues to threaten some 2,800 residences in the coastal city of Goleta, northwest of Santa Barbara.

“The Gap Fire has been fanned by so-called ‘Sundowner’ winds—Santa Barbara's equivalent of the Santa Ana winds,” said Scott Stransky, research analyst at AIR Worldwide. “This type of Foehn wind is much more common in the fall and winter, but it is not out of the ordinary to see it fuel fires in the summer months. The Sycamore Canyon (1977), Wheeler (1985), and Painted Cave (1990) Fires all occurred during Sundowner conditions in summer months.”

Another noteworthy fire—the Basin Fire—continues to ravage land near the famed resort of Big Sur, in Monterey County. On July 1rst, the fire intensified and jumped a fire line set up to protect the town. The following day, some 1,500 residents in the area were ordered to evacuate. As of Sunday, the Basin Fire had consumed 74,985 acres and destroyed 23 residences and 23 outbuildings. It was 11% contained—up from 3% at the end of last week. The Basin Fire continues to threaten 2,500 homes in Big Sur Valley.

“Typically, between 5,000 and 10,000 fires burn each year in California, but lightning strikes—the source of this summer's flames—usually account for only about 10% of fire ignitions in the state,” continued Stransky. “Lack of rain in 2008 left fuels in the area very dry. Also, many of the fires started by lightning were and are burning in chaparral, considered one of the most dangerous fuels in the wilderness. Exacerbating matters, the jet stream shifted far to the north, preventing storms from delivering rain, and although cool air was moving in from the Pacific to aid firefighting efforts earlier today, no rain is expected in the near future.”