Los Angeles is currently grappling with intense Santa Ana winds, which have fueled the devastating Palisades and Eaton fires. This wind event is not only strong but also coincides with an unusual lack of rainfall in the region.
During winter, low-pressure systems called “inside sliders” move south through the Great Basin, causing colder weather in areas east of the Sierra Nevada and warmer, drier conditions in Southern California’s coastal areas.
The ocean tends to hold onto heat better than the surrounding land, creating a stark temperature contrast. This difference in temperature is crucial for the Santa Ana winds, which are typically strongest during the winter months. The winter months usually bring a significant gradient between cool inland areas and warm coastal spots, which intensifies these winds.
When a high-pressure system settles over the coast, it forces cooler, denser air from the deserts to move towards the coast. As this air flows down the mountains of the Transverse Ranges, it heats up and dries out due to a process called adiabatic compression, raising the temperature by about 5°F for every 1,000 feet of descent. This is why Santa Ana winds can feel like standing in front of a powerful blow dryer.
While winter is generally a time of less fire risk, the ongoing drought has left the region parched. Lack of rain has led to dangerously dry conditions across Southern California; in fact, downtown Los Angeles has only received 0.16 inches of rain since the water year began. This makes it one of the driest starts on record. Similarly, Los Angeles International Airport has seen just 0.03 inches, which is exceptionally low.
Nearby areas are feeling the impact too. Palm Springs recorded less than 0.01 inches—a whopping 1.57 inches below average—while San Diego has only gathered 0.14 inches, 3.58 inches below normal. Many locations haven’t seen significant rain in over nine months.
The tinder-dry conditions combined with the strong Santa Ana winds create a perfect storm for wildfires. Unfortunately, more Santa Ana winds are expected soon, although they may not be as powerful as those seen during the recent fires. The fire danger remains high until significant rain arrives, but forecasts do not show any signs of moisture in the immediate future.
