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Diablo Winds and Santa Ana Worsen California Wildfires. Here’s Why.

by Ronniya Varghese Americas Jul 30th 20214 mins
Diablo Winds and Santa Ana Worsen California Wildfires. Here’s Why.

The state of California in the US experiences some of the world’s most intense and destructive wildfires every year. Diablo winds, a dry current that flows from the east or northeast and down into the San Francisco Bay area, can be linked as the contributing cause of California wildfires and prolonged fire season. 

California has a Mediterranean-like climate and is prone to wildfires

Every year, the state of California becomes engulfed by monstrous forest fires. These have led to large-scale property destruction as well as loss of life. Primary causes of frequent California wildfires can be linked to two dry currents called Diablo and Santa Ana. The diablo winds blow primarily over Northern California whereas Santa Ana covers the southern region. 

Record breaking wildfires have been occurring each year, and are worsening with every progressive year. Eight out of 10 of the largest wildfires to have occurred in the last decade destroyed up to 3.5 million hectares of land alone. 

During spring and fall seasons, Diablo winds reach the San Francisco Bay Area and down the western slopes of the Sierra Nevada Mountain Range into the Great Central Valley from the northern coast ranges. These winds are offshore northeasterly winds that originate near the Diablo mountain ranges (hence the name) and flow over Northern California. They originate when there is a high pressure over Nevada and low pressure west of San Francisco and Monterey. As these winds blow from the desert regions of Nevada down to sea level, they warm by compressional heating and lose much of its humidity. Sometimes, this warming can be as much as 20 degrees celsius, and ultimately trigger wildfires. 

Out of the 20 most destructive fires in California, six were caused by Diablo winds: Camp Fire (2018), Tubbs Fire (2017), Tunnel Fire (1991), Nuns Fire (2017), the Atlas Fire (2017), and the Redwood Valley Fire (2017). 

You might also like: 14 Worst Wildfires in US History

The famous wineries in Napa Valley, the most important wine producing region of America, have been facing drawbacks from these fires. Wildfires have begun to coincide with harvest seasons, causing huge losses to the wineries in the area. The most destructive wildfire, Glass Fire, occurred in 2020 which destroyed some historic buildings along with years of wine production.

Farmworkers, who are often undocumented immigrants from Latin America, play an important role in these wineries. They are forced to work under brutal weather conditions and the constant smoke inhalation drastically affects their respiratory systems and health. 

Other Causes of California Wildfires

Although Diablo winds are a big contributor to wildfires in Northern California, there are other factors involved that increase the likelihood of forest fires. Climate change plays an obvious role where drier seasons have increasingly extended, which in turn have prolonged the fire season. Likewise, the rise of urbanisation in these fire sensitive areas also play an active role. In another instance, the combination of a long-term drought, strong winds, and low humidity have been recorded in the lead up to the Camp Fire of 2018, and should be closely monitored.

Studies conducted have also shown periodic variations caused by El Niño–Southern Oscillation (ENSO) influence the climate over California thereby leading to abnormally dry winters which could aid in such fires. 

Slowed But Not Stopped

These fires are a health hazard. Breathing in the smoke can severely affect the lungs, kidneys, liver and even the brain. It leads to severe exhaustion for firefighters who have to tackle fires for days on end. There are even times when the smoke is so dense that the sky turns orange and blocks out the sun in several instances. 

In order to bring the situation under control, and to establish healthy and resilient forests and communities that can adapt themselves to these fires, the Governor’s Forest Management Task Force was created. The task force has recently issued the Wildlife and Forest Resilience Action Plan. They plan to expedite efforts to: 

These historic wildfires caused by climate change and dry currents seem to be the new normal for the state of California. According to National Aeronautics and Space Administration (NASA) former chief scientist Waleed Abdalati, these fires can be slowed but not stopped. With rising temperatures, scientists expect the situation to get much worse in the future with a probability of wildfires increasing up to 77% by the end of the century. Initiatives such as the Governor’s Forest Management Task Force and the involvement of necessary stakeholders along with the US government are the only way forward to constructively tackle this destructive situation.  

Featured image by EO Photographer: Justin Sullivan


About the Author

Ronniya Varghese

Ronniya is a recent Environmental Studies and Sustainability Science graduate from Lund University. She enjoys reading, gardening and identifying solutions to reduce her carbon footprint. She previously volunteered at a farmers' organisation in south Sweden and has also worked in the e-waste recycling sector in India.

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