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The three wildfires that have devastated large parts of the Los Angeles city and surrounding areas in the United States since January 7, 2025, occurred due to rare meteorological conditions enhanced by global warming and consequent climate change, mainly due to a ‘hydroclimate whiplash’.
The region affected by the fires was 5 degrees Celsius warmer, up to 15 per cent drier and up to 20 per cent windier, according to a study by climate attribution group ClimaMeter, published on January 9. Wind gusts of up to 161 kilometres per hour within the seasonal Santa Ana winds and rare fire tornadoes have been observed within the fires.
The blazes have already killed 24 people and burnt 12,000 structures to the ground over an area of 155 square kilometres as of January 13 and may intensify further due to fierce winds in the coming days.
“We ascribe the strengthened winds, higher temperature and drier conditions triggering January 2025 California wildfires to human-driven climate change and natural climate variability likely played a minor role”, said ClimaMeter on its website.
The Santa Ana winds that are responsible for the sustenance and proliferation of the Palisades, Eaton and Kenneth wildfires “occur when air from a region of high pressure over the dry, desert region of the southwestern US flows westward towards low pressure located off the California coast”, according to the National Weather Service (NWS) of the US.
The winds flow from the west to the east through the mountain valleys of Southern California and are common during the cooler months from September till May. As the dry winds pass down the slopes of the mountains, they become compressed and warm.
When these winds combine with other enabling factors such as low levels of precipitation and humidity and warmer long-term air temperatures, they increase the risk of intense wildfires such as what has occurred in California in the last few days.
As of January 7, 2025, almost 36 per cent of California was under moderate to extreme drought conditions, according to the US Drought Monitor. Another 25 per cent of the state was also exceptionally dry.
The entirety of Los Angeles County was under drought conditions, with 60 per cent suffering from severe drought and the rest undergoing moderate drought conditions. The wet season for the region, which generally begins in October, has been exceptionally without precipitation in 2024-2025. There is a forecast of little to no rain in the comings days.
The extreme dry conditions in the current season were preceded by a predominantly wet season in early 2024, which had aided the growth of vegetation.
This creates a ‘hydroclimate whiplash’ condition wherein an extremely wet season is succeeded by an extremely dry season, according to a research paper published in the journal Nature Reviews Earth & Environment on January 9, 2025. Moreover, the dry conditions in California frequently overlap with the Santa Ana winds season, creating the perfect conditions for intense wildfires.
“California’s fire season has already lengthened considerably in a warming climate. Critically, this has increased the overlap between ‘critically dry vegetation season’ and ‘offshore wind season’ (Oct-Jan),” Daniel Swain, climate scientist at the University of California, Los Angeles and lead author of the research paper, told the publication Yale Climate Connections.
Such ‘hydroclimate whiplash’ conditions have increased by 31-66 per cent in three-month periods (sub-seasonal) and by 8-31 per cent in 12-month periods (inter-annual) across the world since the middle of the 20th century, according to the paper. With further warming of 3°C, the increase of ‘hydroclimate whiplash’ may increase by 113 per cent in the sub-seasonal periods and by 52 per cent in inter-annual periods.
The Palisades fire that originated in the Santa Monica mountains is still raging in the western parts of Los Angeles city, while the Eaton fire is engulfing the northern parts of the city with more severe fire warnings in place till at least Friday, January 17, 2025.
NWS has issued a red flag warning of ‘Particularly Dangerous Situation’ for parts of Los Angeles County for January 14-15, as the wind gusts will peak at 113 km / hr and the relative humidity levels could be as low as 8 per cent in the region.