Rain and snow to elevate flood risk in California

AccuWeather

A storm is expected to bring significant rainfall to Southern California, which could lead to the elevated risk of flash flooding and mudslides in the burn scar areas from last month's wildfires.

Transcript

00:00So far, John, during the winter months, it's been Northern California that have gotten

00:05the lion's share of rain with these storms, but this is the first storm where it's going

00:11to be the opposite.

00:12This is easily the wettest storm in Southern California this season.

00:17It sure is, Bernie, and normally, even in a typical year, we'd be talking about that

00:22bringing the risk for flash flooding, but the fact that we've had these devastating

00:27wildfires around the L.A. area means that we have a lot of burn scars, and those are

00:32the areas that are especially susceptible to flash flooding.

00:34Look at the amounts here.

00:36We're talking about a widespread two to four inches of rain across coastal sections of

00:41California, right down into the Los Angeles basin, and then also in the higher elevations

00:46nearby, four to eight inches of rain.

00:49And the bigger thing, even beyond just the amounts of rain, is going to be how fast that

00:54rain is falling.

00:55You've heard us talk about that often, and that rain rate, which could be a half inch

00:59or more per hour, especially in those thunderstorms, is very concerning for the risk for mudslides

01:05and life-threatening flash flooding.

01:07John, oftentimes in California, we talk about rain as short-term pain, long-term gain.

01:13Let's go over the short-term pain first.

01:15Unfortunately, it looks like there could be a lot of that with this setup, especially

01:19you saw on that future radar animation, Bernie, you just showed those yellows and reds.

01:25That's intense areas of rainfall that are going to persist over the same areas, first

01:29from near the Bay Area, but then by later tomorrow into portions of the L.A. area, poorly

01:35timed with the evening commute, with those downpours, and especially where those downpours

01:40persist, that's where those flash flooding risks will be elevated, and landslides, mudslides

01:45and rockslides, all a concern, especially near those significant devastating wildfires

01:51that occurred near Altadena and also Pacific Palisades and surrounding areas.

01:57Places there and downhill from there are going to be especially at risk for more damage.

02:02Now, the long-term gain is going to be the drought.

02:05We have a short-term drought in Southern California, and I'll tell you what, John.

02:08This will be the first month in several months where we're probably going to see above the

02:13historical average rainfall in Los Angeles and perhaps even in the San Diego, so that's

02:19good news.

02:20But in review, John, let's talk about this number that we continue to stress on the damage

02:28that these fires accrued for the economic loss of those fires in Southern California.

02:35It was a staggering loss of $250 to $275 billion from those fast-moving, wind-driven infernos,

02:43and AccuWeather has stressed that this is going to be a long tail of impacts, and so

02:48when you look at the damage that's occurred, it's not only the damage, and some other sources

02:54are just talking about the damage that has occurred.

02:56We're talking about the long tail of medical and health impacts and also all the impacts

03:02to businesses failing, job losses, loss of tourism dollars, and those long-term medical

03:07costs from physical and mental health issues, plus the cost of cleanups, which is going

03:12to be very significant.

03:13And now, Bernie, the concern here is that with this rainfall, the flash flooding concerns

03:18and also we've got a lot of concern over polluted water perhaps running off from these

03:24areas that experienced the burning, so lots of problems here.

03:28And unfortunately, John, this is going to be a problem for the next year or two.

03:31Anytime it rains heavy, those burn scars are going to be susceptible to debris flows and

03:37mudslides.

03:38Sure is.

03:39AccuWeather Chief Meteorologist Jonathan Porter, John, thanks for helping us break it down

03:43here this morning.

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