Scientists at Scripps Institution of Oceanography say climate change will alter the pattern of Santa Ana winds and move the peak Southern California fire season into the winter.
Climate scientists Janin Guzman-Morales and Alexander Gershunov report in the journal Geophysical Research Letters Thursday that Santa Ana winds will become less frequent in early and late parts of the traditional October to April season.
But the winds will grow in relative intensity and duration during the winter, shifting the peak fire season.
“In December, back-to-back [Santa Ana winds] are most probable, providing opportunities for wildfires to burn longer and bigger,” the authors write. “In the future, the probability of back-to-back events will diminish somewhat, but will still remain much stronger in December than it ever was in October, or even November.”
A succession of Santa Ana wind events fanned what became the largest fire in Southern California history, the Thomas Fire, in December 2017. The fire burned 440 square miles in Ventura and Santa Barbara counties before being contained in January 2018.
The authors do not address whether the change will result in more or fewer total wildfires but note that the Thomas Fire was “likely a harbinger of wildfire seasonality we would expect to experience more often in the future.”