California Experiencing Unusually Low Number of ‘Major’ Wildfires in October: Here’s Why

by Shelby Scott
(Irfan Khan / Los Angeles Times via Getty Images)

Across the American West, but in California especially, fall marks the most dangerous time for wildfires. Typically, months of hot, dry weather combine with strong winds, putting brittle vegetation at risk of sparking and causing widespread wildfire damage, especially in October. This year, however, things are different. A cooler, damper weather pattern in the Bay Area has left California with essentially no major wildfires burning anywhere in the state. And we’re here to take a look at why.

According to The Mercury News, experts believe the lack of California wildfires throughout October this year is because of a “decent” burst of rain in mid-September. Days of rain soaked most regions in both the north and south ends of the state. Once the rains subsided, the Bay Area then welcomed several weeks of cooler, foggy conditions. Jan Null, a meteorologist with Golden Gate Weather Services in Half Moon Bay, remarked on how the dreary weather has significantly lessened the threat of major wildfires in California.

“This pattern is really good as far as fire weather,” she said. However, for Californians looking to enjoy warm sunny days at the beach, the opposite is true.

That said, forecasters, climate scientists, and firefighters alike are surely relieved by the break in major wildfires. Per the outlet, four of the five deadliest wildfires in California have taken place in October or early November. These include the 2018 Camp Fire, the Oakland Hills Fire of 1991, and the Wine Country Fires of 2017.

What’s Causing Cooler Weather in California This Wildfire Season?

While wildland firefighters especially are likely enjoying a break from historically destructive wildfires this month, there’s a reason California is seeing decreased numbers of major blazes right now.

According to the news outlet, the favorable weather conditions rolling in from the Bay Area are the result of what forecasters call a “Rex Block” which has settled over the Pacific Coast. Basically, a Rex Block pattern is the result of a combined high and low-pressure system. Typically, a high-pressure system off of California’s coast helps to block storms. In comparison, low pressure systems aid in drawing storms in from the Pacific. A Rex Block pattern occurs when both pressure systems exist near one another.

This month, forecasters state that a high-pressure system has been hanging over the Pacific Northwest while a low-pressure system remains steady over the Channel Islands. Together, they alter wind patterns which, at the moment, continue to bring cooler, wetter weather in from the ocean. Per the outlet, these wind patterns function as “nature’s air conditioning.” In turn, this stops hot, dry weather from the desert from blowing west, which helps raise wildfire danger across California.

National Weather Service meteorologist Sean Miller offered insight about the Rex Block preventing wildfires across the state.

“With cooler temperatures, more moisture and not having strong winds off the land, those conditions aren’t super conducive to spreading wildfires. It’s not to say you can’t still have fire,” he explained, “but if it develops it doesn’t spread as rapidly.”