Although wildfires in California are typically at their worst in fall months, the Los Angeles Times reported that the Thomas fire in Ventura County has forced 27,000 people to evacuate, burned over 50,000 acres, and destroyed at least 150 structures. As the fires rage on, there isn’t much hope that this wildfire will be contained in the very near future. So why are these wildfires in California occurring in December? The weather leading up to and during this winter month is to blame for these devastating fires.

In an article about why the 2017 wildfires have been some of the worst in California’s history, the Los Angeles Times wrote,

In its story on the Thomas fire, the Times explained that in the past few years, rain has occurred before the Santa Ana winds, making them less dangerous. But this time, they follow a three-month dry spell. So when the Thomas fire started during the night of Monday, December 4th in the foothills in Santa Paula, the fast-moving winds hit the dry land and spread the fires. The paper reports that the National Weather Service said this is “the strongest and longest duration Santa Ana wind event we have seen so far this season,” and it’s expected to last at least until Thursday.

As the Los Angeles Times reports, a 2015 study on fires in Southern California found that, during the Santa Ana season, wildfires cause more structural damage than fires that occur in the summer months. The Santa Ana season runs from late September to the end of the year, and the 10 worst wildfires in California’s history all happened between these end-of-the-year months.

So even though the December 2017 fires are catastrophic, they aren’t rare.

However, KCET reported on that same 2015 study, stating that the research “found that destructive fires in California have increased in both number and severity over the last decades.” And the authors partially blamed climate change for the increase.

In another article about how the wind is to blame for the spread of these fires, the Los Angeles Times noted that December usually has 10 days of Santa Ana winds. By the end of this week, six days of Santa Ana winds will have already occurred, which means the winds aren’t over yet. But hopefully, once this round of wind stops, firefighters will be able to contain the fires and stop them from spreading before they cause any more destruction. Even then, one of California’s worst wildfire seasons won’t be over yet.