Santa Ana winds increases fire threat in Southern California

AccuWeather

AccuWeather California Expert Ken Clark warns of an increased fire threat in Southern California due to the effects of Santa Ana winds blowing from the mountains with gusts of 40-80 mph possible.

Transcript

00:00Accuweather meteorologist and California expert Ken Clark. Ken Clark has four decades of experience

00:08here at Accuweather and he joins us from Rancho Cucamonga here this morning in California. You

00:14know, Ken, of course, as a Southern California native and those that live in Southern California,

00:19the term Santa Ana winds is well known, but for those that live elsewhere in the country,

00:24it may be a little bit of a mystery. Let's break down what the Santa Ana is.

00:30Sure, it's winds that basically blow from northeast to southwest across Southern California.

00:35They go from the deserts to the coast and they're amplified by several factors. One is how strong

00:40the winds are aloft, how strong the pressure gradient is from the inland areas to the coast,

00:45and if everything is aligned right and the strongest winds are throughout the depths of

00:50the atmosphere, we get the very strongest winds such as the case today. These are very dry winds.

00:56They dry out as they cross the mountains and descend into the coastal areas, and that's why

01:00we not only have windy conditions in this kind of situation, but we also have a very high fire

01:07danger because the relative humidities get to be very, very low. Yeah, and let's go over the

01:12pattern, Ken, that's producing this. I want to show you the water vapor loop. You can see that

01:17big dip in the jet stream. There it is coming across Nevada and into Utah, and it's on the

01:23western side of that jet stream. In this place, the upper low, you could see the winds coming in

01:31out of the east-northeast or the north-northwest, Ken, and that's the problem. And again, it doesn't

01:37necessarily mean it's right at the coast, but it's almost like water through a pipe, right? It goes

01:42through those canyons and passes and it just accelerates. There are favorite areas that get

01:47these kind of winds. Ventura County, especially Ventura County coastal areas, the mountains,

01:53down across parts of the Inland Empire, eastern L.A. County, San Bernardino County, and across

01:59Orange County as well, and all the mountains of Southern California. Actually, downtown L.A.

02:04doesn't get a lot of Santa Ana winds. It happens very rarely. They're shielded from it, but other

02:09areas are not, and those are the areas that have the extreme fire danger we have right now.

02:15And again, let's talk about how strong this setup is.

02:19Right now, we're experiencing winds of 25 to 45 miles per hour. I've seen gusts as high as

02:24Hurricane Force across the Orange County mountains this morning, 77 miles per hour at Fremont Canyon

02:32about an hour ago. It may be even stronger than that right now. These high mountain areas can get

02:37wind gusts that are very, very strong that people don't really see but are occurring,

02:42and they are important for one thing. A lot of the high transmission power lines cross these

02:47high mountains, and we have a danger of these higher tension wires coming down in these kind

02:54of high wind situations. And that's why, Ken, we have something we haven't seen.

02:59This was very surprising to me. We have an extreme fire danger today. When's the last time we had

03:05that? We haven't had one like this since 2020. The National Weather Service office in Los Angeles

03:11issued a PDS or particularly dangerous situation for the fire weather across portions of Southern

03:17California, and that hasn't happened since December of 2020. And Ken, explain really quickly,

03:27how much of a problem does this cause in Southern California?

03:33Unfortunately, as a fire takes place, especially this morning into this afternoon,

03:38it can grow extremely quickly. I mean, we're talking going from an acre fire to hundreds of

03:44acres of fire in less than an hour, and they get out of control. There's no way to control them,

03:50basically because the winds are so strong. They can't send up airplanes to drop

03:55a FOS check, which helps to keep the fires down. They can't do water droppings. They can't send in

04:02really fire crews in this kind of situation either. So this is why it's a particularly

04:06dangerous situation. Fires spread very rapidly. Let's hope that doesn't occur,

04:11but it is a very much of a possibility.

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