Santa Ana Wind Analysis for the Palisades and Eaton Wildfires

The Palisades and Eaton fires together burned over 37,000 acres, destroyed over 17,000 structures, and resulted in the loss of 29 lives. These fires started on January 7, 2025, and spread rapidly as wind-driven fires, with wind dictating the rate and direction of spread. The high rate of spread in densely populated areas completely overwhelmed evacuation and fire containment activities. This type of wind is locally known as a Santa Ana wind in Southern California. Santa Ana winds occur when a strong inland high-pressure system creates a strong offshore pressure gradient, producing winds that blow from the east to northeast. Climatologically, Santa Ana winds peak in frequency and intensity during January.?

Wind-driven wildfires at the wildland urban interface within and near mountainous terrain remain one of the greatest areas of natural disaster consequence. There have been a number notable wind-driven wildfires to illustrate this fact - Camp (2018), Marshall (2021), and (Lahaina 2023). These fires along with the Palisades and Eaton were all associated with a type of downsloping windstorm when air that is forced over mountainous terrain is able to accelerate over the barrier and then move into nearby lower lee-side elevations. The particulars around downsloping winds are sensitive to a variety of atmospheric factors, such as stability (change in temperature with height) and the strength of wind speed, with potentially wide-varying differences across short distances. After wildfire ignition, a self-reinforcing environment can develop with the heat from the plume becoming a mixing agent to increase or sustain high winds resulting in even more aggressive firestorm behavior.?

Analysis provided by Disaster Tech shows that the Palisades Fire featured peak winds that reached 60 to 70 mph on January 7 to 8, 2025 from the north-northeast. This wind information is based on 3-km resolution gridded observed wind information from NOAA’s Unrestricted Mesoscale Analysis System; wind information uses standard meteorological convention of 10-meter elevation 3-second wind gust within an open area. The duration of high winds was fairly long, with winds reaching 45 mph or greater within the fire perimeter for over 12 hours.?

The Eaton Fire featured peak winds that were even stronger, reaching hurricane force (70 to 80 mph) on January 7 to 8 from the north-northeast. The duration of high winds was fairly long, with winds reaching 45 mph or greater around the fire for over 24 of 48 hours on January 7 and 8.?

From a meteorological perspective, the predictability of such high wind potential is fairly good within a few days prior to potential events. Hyperlocal nuances will always be difficult to resolve. Terrain-driven high winds are basically a type of localized “inland hurricane”, and should be more respected. The risk-consequence of what happens if a wildfire ignition occurs is more difficult to understand. Mental models about risk can easily underestimate the risk potential, with such an evolving risk landscape.?

Advances in fire science and meteorological modeling allow for risk to be understood like it never has before. For example, more realistic simulations showing potential fire movement and impacts can be used to inform evacuation and other emergency response plans, or repurposed as evergreen training materials to help everyone more universally prepare for and respond to the next disaster.