The Santa Ana winds in Los Angeles dry out the hills, making them more susceptible to fires.
Strong winds happen when cold air builds up in Nevada and Utah, then moves west towards California’s mountains where it becomes warm and dry.
Dry plants and fire spreading –
Santa Ana winds can set the stage for dangerous wildfires or intensify existing ones by drying out the vegetation.
They intensified the fires in the Palisades area, burning 9,500 hectares, and the Eaton fire, which spread to 14,000 hectares by fanning flames and hot coals through the untouched dry vegetation.
The National Meteorology Service forecasted “extreme fire behavior” due to winds reaching speeds of up to 110 kilometers per hour, creating a “particularly dangerous situation (PDS)” as firefighters battled the flames.
Hottest and arid atmosphere –
The Santa Ana winds typically occur frequently from September to May for several consecutive days.
When a high-pressure system develops above the deserts in eastern California, it moves the air towards the Pacific coast.
As the air moves down the mountains of Santa Ana and Sierra Nevada and passes through the valleys, it becomes compressed, heated, and loses moisture.
Southern California used to experience hot and dry winds that resulted in trees falling and dust clouds forming. In 2017, the Santa Ana winds sparked the Thomas fire, leading to the destruction of over a thousand buildings.
Last week, the winds reached a level of intensity not witnessed since 2011, with gusts reaching speeds of up to 160 km/h, as stated by meteorologists.