Firefighters on standby as damaging winds return to Los Angeles

The Santa Ana winds are forecast to batter Southern California again, fuelling dangerous fire conditions over the next few days.

At 6am AEDT on Monday, the US National Weather Service issued a red flag warning about extremely critical conditions for the Malibu Coast with northeasterly surface winds up to 48-64km/h and gusts around 97-113km/h.

A weather system is expected to hit Southern California late on Monday afternoon AEDT, bringing amplified winds and “dangerous fire-weather conditions” from mid-morning Tuesday until early Wednesday AEDT.

A critical warning was also extended to the coast in Orange County and northern San Diego County, where northeasterly surface winds could reach 32-48km/h.

Conditions in some parts of the windprone mountains, foothills and valleys of inland Orange and San Diego Counties will be extremely critical.

The Santa Ana winds are an example of a “foehn wind”, which blows up one side of a mountain and down the other side, becoming hotter and drier as it descends.

Foehn winds are found all over the world, including Australia where they blow from inland to the coastal side of the Great Dividing Range.

The effect is stronger in Los Angeles because the San Bernadino Mountains are so tall and wide – the range tops out at 3506 metres, in contrast to Australia’s largest mountain, Kosciuszko, at 2228 metres. In Los Angeles, some of the winds are also funnelled into mountain passes and canyons, becoming faster like a river that suddenly narrows and turns into rapids.

A Santa Ana wind can plunge humidity to the single digits, causing vegetation, both living and dead, to dry out and become more flammable. This is exacerbated by climate change increasing the fire risk – Los Angeles is in drought, and the American Southwest has been drying out for 50 years.

The warnings come as firefighters continue to battle two major blazes in the Los Angeles area, the Palisades and Eaton fires, which have destroyed more than 14,000 structures since they broke out during fierce winds on January 8 AEDT. The Palisades Fire was 52 per cent contained on Monday morning AEDT and the Eaton Fire 81 per cent contained, fire officials said.

Dan Collins, a spokesperson for the Palisades Fire incident, said they had made progress on the perimeter of the Palisades Fire, which has charred more than 96 square kilometres near the Pacific coast, but there were areas inland that continued to burn.

“There is always a possibility in a red flag warning something hot, or some type of burning material from the interior, could be perhaps whipped up and blown across the containment lines,” Collins said.

Carlos Herrera, a spokesperson for those fighting the Eaton Fire further inland, said firefighters were fairly confident it would remain contained, but were concerned a new fire could break out because of dry vegetation.

California Governor Gavin Newsom has positioned 45 fire engines across the region, as well as water-dropping aircraft and hand crews to enable a quick response.

With AP