Santa Ana winds trigger high wildfire threat

AccuWeather

AccuWeather California Expert Ken Clark explains Santa Ana winds and the threat they possess to spread wildfires in Southern California.

Transcript

00:00Joining you right now is AccuWeather meteorologist and California expert Ken Clark. Ken Clark has four decades of

00:10experience here at AccuWeather and he joins us from Rancho Cucamonga here this morning in California.

00:16You know Ken, of course, as a Southern California native and those that live in Southern California,

00:20the term San Ana Winds is well known, but for those that live elsewhere in the country,

00:26it may be a little bit of a mystery. Let's break down what the San Ana is.

00:32Sure, it's winds that basically blow from northeast to southwest across Southern California. They go

00:37from the deserts to the coast and they're amplified by several factors. One is how strong the winds

00:43are aloft, how strong the pressure gradient is from the inland areas to the coast, and if

00:48everything is aligned right and the strongest winds are throughout the depths of the atmosphere,

00:53we get the very strongest winds such as the case today. These are very dry winds,

00:58they dry out as they cross the mountains and descend into the coastal areas, and that's why

01:02we not only have windy conditions in this kind of situation, but we also have a very high fire

01:09danger because the relative humidities get to be very, very low. Yeah, and let's go over the

01:14pattern, Ken, that's producing this. I want to show you the water vapor loop. You can see that

01:19big dip in the jet stream. There it is coming across Nevada and into Utah, and it's on the

01:25western side of that jet stream in this place, the upper low. You can see the winds coming in

01:33out of the east-northeast or the north-northwest, Ken, and that's the problem. And again, it doesn't

01:39necessarily mean it's right at the coast, but it's almost like water through a pipe, right? It goes

01:44through those canyons and passes, and it just accelerates. There are favorite areas that get

01:49these kind of winds. Ventura County, especially Ventura County, coastal areas of the mountains,

01:55down across parts of the Inland Empire, eastern LA County, San Bernardino County, and across Orange

02:01County as well, and all the mountains of Southern California. Actually, downtown LA doesn't get a

02:06lot of Santa Ana winds. It happens very rarely. They're shielded from it, but other areas are not,

02:12and those are the areas that have the extreme fire danger we have right now.

02:17And Ken, let's talk about how strong this setup is.

02:22Right now, we're experiencing winds of 25 to 45 miles per hour. I've seen gusts as high as

02:27Hurricane Forest across the Orange County mountains this morning, 77 miles per hour at

02:33Fremont Canyon about an hour ago. It may be even stronger than that right now. These high mountain

02:39areas can get wind gusts that are very, very strong that people don't really see but are

02:44occurring, and they are important for one thing. A lot of the high transmission power lines cross

02:48these high mountains, and we have a danger of these higher tension wires coming down in these

02:56kind of high wind situations. And that's why, Ken, we have something we haven't seen, and this was

03:02very surprising to me. We have an extreme fire danger today. When's the last time we had that?

03:08We haven't had one like this since 2020. The National Weather Service office in Los Angeles

03:13issued a PDS, or Particularly Dangerous Situation, for the fire weather across

03:18portions of Southern California, and that hasn't happened since December of 2020.

03:23And, Ken, you know, how bad, or explain really quickly, I mean, how much of a problem does this

03:31cause in Southern California? Unfortunately, as a fire takes place, especially this morning

03:38into this afternoon, it can grow extremely quickly. I mean, we're talking going from an

03:44acre fire to hundreds of acres of fire in less than an hour, and they get out of control. There's

03:50no way to control them, basically because the winds are so strong. They can't send up airplanes

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

04:02can't send in, really, fire crews in this kind of situation either. So this is why it's a

04:07particularly dangerous situation. Fires spread very rapidly. Let's hope that doesn't occur,

04:13but it is very much of a possibility. AccuWeather California expert

04:18meteorologist Ken Carr. Ken, thanks for breaking it down.

Category

Transcript

Recommended