‘Particularly dangerous’ wildfires return to California and could persist for months, experts say | California wildfires

When it comes to predicting catastrophic wildfire conditions in California, there are two main ingredients: fuels (think grasses, shrubs, trees – basically anything available for fires to burn ) and the winds.

When analyzing fuels, forecasters primarily look at drought levels, as well as recent rainfall that could help mitigate the effects of a long-term drought. With winds, in Southern California at least, it’s about anticipating the Santa Anas – the strong winds that blow offshore, from the deserts to the coast, bringing with them a lot of dry air.

For the next week, a series of weather and climate models bring good and bad news for Southern California:

The good news is there are no signs on the horizon of a near Santa Anas windstorm last week that brought record wind gusts of 100 mph to Los Angeles.

The bad news is that it looks like Los Angeles’ record-breaking start to the rainy season is going to continue to get worse.

Over the next three days

A low pressure system stuck offshore this week will mark the return of strong Santa Ana winds.

The U.S. National Weather Service (NWS) in Los Angeles has upgraded its fire weather forecast for this week to “particularly dangerous,” its highest alert level. “Winds will be strong enough to potentially cause explosive fire growth,” he said during a forecast briefing. “Don’t do anything that could start a fire.” In California, about 95% of fires are “human caused.” This rarely means arson, more often things such as a dragging trailer chain from a truck, downed power lines, or discarded cigarettes.

The NWS expects offshore winds gusting up to 70 mph, particularly in Ventura and Los Angeles counties between Tuesday morning and Wednesday afternoon, bringing relative humidity down to 5% and allowing extreme fire behavior and long-distance transport of burning embers. Conditions in Ventura County in particular could be worse than last week.

In the coming days, fuels will reach a record high for this time of year all along the Central Coast and potentially in the Bay Area. Fuel drought – the amount of water that has been removed from trees, grasses and shrubs by the current drought – is approaching and will soon exceed what is typically seen at the height of wildfire season, at midsummer on the southern California coast.

Over the next three weeks

This year’s rainy season is just 2 percent of normal in Los Angeles, which has received just 0.16 inches of rain so far.

Weather models are increasingly indicating that Southern California will receive no rain during the remainder of January, and potentially no rain during the first or second week of February as well.

It’s really unusual. January and February are the wettest months of the year in Los Angeles, averaging more than 7 inches of the city’s 13 inches of rain in a typical year. Even during the winter of 2006-2007, the driest year in Los Angeles history, the city still received just over 3 inches of rain.

Intensifying drought conditions mean the current series of extremely unseasonable fires will continue with the resurgence of moderate to strong Santa Ana winds.

New signs are emerging in longer-term weather models that the current weather situation could become persistent – ​​and settle into what is known as a blocking situation. If a blocking pattern, particularly a “Rex block”, were to establish, it would continue to shift moisture from the Pacific either northward toward Alaska or further southward toward Mexico, thereby worsening the drought. in California.

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Over the next three months and beyond

According to the NWS, drought intensified last week in Southern California and will continue to worsen through March.

This year’s historically low rainfall comes after more than 25 inches of rain fell in each of the past two rainy seasons, encouraging the growth of shrubs and grasses that now serve as potential fuel.

This type of “weather whiplash” is a characteristic signal of the climate crisis.

If and when the rains come later this year, there’s a good chance they will come courtesy of a river of atmospheric moisture that would increase the risk of flooding and mudslides in the vast scars of the Palisades fires and by Eaton.

Early January also marked the official arrival of La Niña conditions in the tropical Pacific Ocean, which tend to precede drought years in Southern California.

Taking into account seasonal weather forecasts for the next seven months, Los Angeles is expected to receive between 4 and 7 inches of rain for the remainder of this year’s wet season, with some potential wiggle room above and below that. fork.

If these predictions are confirmed, dangerous fires would continue not only over the next few weeks, but throughout the summer and beyond – and could spread to Northern California.