Between November 2022 and May 2024, Eaton Canyon has experienced an extraordinary number of rainstorms, including atmospheric rivers, lightning storms, cold fronts, monsoon surges, and even its first landfalling tropical cyclone in 87 years. These remarkable storms have collectively delivered between 75 and 100 inches of rainfall throughout the canyon, marking this the wettest 18-month period in 117 years of recorded weather history. Today, a walk through the canyon reveals an unfamiliar landscape, with moss-covered trees, lush poison oak, and dense vegetation in nearly every direction. In some areas, the scene looks much more like a subtropical rainforest than a semi-arid mediterranean climate. This excess rainfall has also meant relief from our historic megadrought, increased biodiversity, and healthy water levels in Eaton Creek.
During that same 18-month period, however, average temperatures in Eaton Canyon have been 5.37°F above the preindustrial average. This combination of extreme wetness and heat is unprecedented in recorded history and likely unmatched in the past 3,000,000 years since Earth was last this warm.
Despite the current beauty of the canyon, there is a danger hiding in the brush; one that has the potential to destroy everything we know and love.
For many, the photograph above showcases Eaton Canyon’s incredible untamed, natural beauty. The thick brush is full of fungi, lichens, mosses, invertebrates, birds, and even the occasional mammal. However, for those wildfire-cautious among us, the scene above is also rather alarming. Unlike many parts of the word, California experiences an annual summer drought from June through November, during which rainfall is minimal or nonexistent. This lush vegetation is not expected to get any appreciable precipitation for the next 6 months, and it is therefore expected to dry out.
Wildfires need three main ingredients to ignite: oxygen, heat, and dry fuel. California’s wildfires are significantly influenced by the availability of dry fuel, such as dead trees, leaf matter, and chaparral brush. The relationship between wet and dry years plays a crucial role in determining wildfire risk:
- Wet year followed by a wet year: Abundant fuel that remains too wet to burn explosively.
- Dry year followed by a wet year: Limited fuel that remains too wet to ignite easily.
- Wet year followed by a dry year: Abundant fuel that becomes dangerously dry. (see: 2020 California firestorms)
- Dry year followed by a dry year: Limited fuel that is highly flammable.
Throughout summer and autumn 2024, the vegetation in Eaton Canyon will likely remain too wet to support an explosive wildfire, as both 2023 and 2024 were much wetter than average. However, if winter 2025 is dry, the massive amounts of fuel in the canyon will continue to dry out, posing an extraordinarily dangerous situation come summer and autumn 2025. Radically increasing summer temperatures also increase evaporation which accelerates the drying-out of fuels.
Eaton Canyon will be destroyed by a wildfire again sometime in the future, just like it was in 1978 and 1993. With the area hotter than ever before and thick brush overcrowding the canyon, this time it could be far, far worse.