First hurricane to hit California in 84 years | Hacker News Reader

First hurricane to hit California in 84 years

washingtonpost.com

119 pointslaurex118 comments

I pay close attention to Tropical Tidbits for Atlantic storm season, their latest on this storm: https://www.youtube.com/watch?v=FJlBocxz0gs

No sensationalizing, just meteorology.

I also like Joe and Joe for the same reason, they usually do a Sunday morning show. Bit more long form. Both retired meteorologists: https://www.youtube.com/@JoeCioffiweather

Daniel Swain, a climate scientist who covers the western end of the US.

https://twitter.com/Weather_West/

Does a thing called 'Virtual Weather Office Hours', often daily if there's a lot going on (or about to be going on)

https://www.youtube.com/@WeatherWest/streams

Here is a flood-risk modelling of Los Angeles area published last year - https://storymaps.arcgis.com/stories/80af8f6b7b8749258b3305f...

This map looks like a topomap. According to said map, I will be 1 meter underwater in a 100 year flood. But the map also looks to ignore the 4 meters of steel/concrete lined channel that run behind my neighborhood. FEMA puts me in zone X (500 year flood zone).

I could swear I remember some kind of tropical storm/hurricane remnants hitting SoCal late last summer or maybe the summer before - was I dreaming of the future again?

Edit: It was hurricane Kay: https://en.wikipedia.org/wiki/Hurricane_Kay_(2022)

You might be thinking of an Atmospheric River / "pineapple express"? While that phenomenon may originate from roughly the tropics, it's not the same as a Tropical Storm.

Nope. This was hurricane remnants coming up from the south. I even recall tuning into some SoCal news stations for some live coverage. The atmospheric rivers come in the winter - this was late summer. Maybe it had weakened more and wasn't considered a tropical storm then, maybe just a tropical depression.

Edit: maybe it was hurricane Kay? https://en.wikipedia.org/wiki/Hurricane_Kay_(2022)

"As Kay moved northward, it transitioned into a post-tropical cyclone overnight 9–10, not far southwest from San Diego, California"

It was tropical storm Kay last year. It weakened to a post tropical storm some ways away from San Diego and ultimately turned back south. Though you are correct that it did have some impacts to California.

Yeah, that's the one I'm remembering. I kept hearing "this hasn't happened in 84 years" and was thinking, didn't it just happen last year? But apparently Kay was a good bit weaker than Hilary will be when it arrives in San Diego.

Some serious impacts. That storm started over 600 wildfires via lightning strikes. It overwhelmed the fire fighting system in California especially since we had serious COVID lock downs in effect and 10% of the firefighters were not available. They had been released from prison due to COVID. Much of the Santa Cruz mountains burned. In northern California a fire was left burning for about a month before it finally flared up and ended up burning over a million acres. Six weeks when the air was so bad that people in my area were advised to not go out doors. That was a big motivator for me leaving the state.

Yeah I recall seeing the images out of SF last year where the sky just had an otherworldly color to them. Here in the northern reaches of the country this summer we’ve had our fair share of wildfire smoke out of Canada—probably something like 2 days a week on average when the wind lines up. But yeah, nothing like what was going on in CA last year.

>otherworldly color

orangeish, as I saw it.

I was in India and read the news and saw the photos too.

Both freaked me out. And the Australia fires had been around the same time, +/- a year or so.

Similar damage.

Yeah, I remember it well because it put out a nasty wildfire that forced a lot of our neighbors to evacuate.

As one person out it, “When you’re praying for a once-in-generation hurricane to come save your home, that’s a stressful week”

It’s threatened a few times but turned away in the last decade or so.

Remnants from hurricanes or tropical storms fairly often make landfall in California as something less than a tropical storm [0], Hilary looks likely to be the first to hit California as a tropical storm since 1939 (the last to hit as a hurricane appears to be in 1858, but Hilary isn’t, contrary to the headline, expected to hit as a hurricane, either.

Also, peripheral effects of a storm that is a tropical storm or hurricane may hit California without the storm making landfall in California.

[0] by the NOAA definitions, where a tropical cyclone with wind speeds up to 38mph is a “tropical depression”, one with winds of 39-73mph is a “tropical storm”, and one with wind speeds over 74mph is a “hurricane”.

Looks like last tropical storm to hit CA was from hurricane Nora in 1997: https://en.m.wikipedia.org/wiki/Hurricane_Nora_(1997)

Edit: ok I see it might have been downgraded to tropical depression by the time it hit CA

Edit 2: apparently it did hit CA as a tropical storm but it does not count as “landfall”: https://www.fox10phoenix.com/news/the-last-time-hurricane-tr...

List of California Hurricanes: https://en.wikipedia.org/wiki/List_of_California_hurricanes

Note, Hilary won't be Hurricane by the time it hits California. Just a Tropical Storm.

That's not how this works. It's the water, not the wind. This is completely unprecedented

I know. I live in Los Angeles. Last winter we had 12 atmospheric rivers over 2 or 3 months, each dumping as much water in a 24h period as Hilary is expected for our area.

Areas like Palm Springs, though, are expecting much more and I’m worried about my friends there.

However, to say a hurricane is hitting California is hyperbole. I’ve been in hurricanes in both Florida and New York.

Unprecedented? How about when the Central Valley fills up with water every 300 years? Is someone actually claiming that this is never happened in the history of California?

There’s nothing “just” about tropical storms.

For some people it is. A tropical storm doesn't even shut down schools here.

Some folks are being ignorant and dismissive with "just", and some are relating their personal experiences.

I have caught myself saying "just 2 inches of rain" since we get that frequently, sometimes in an hour or two. For many people that is a dangerous and life changing amount of rain... and that can be easy to forget if it isn't for you.

tldr; hanlon's razor

> For some people it is.

There is nothing “just” about tropical storms with tracks over the State of California.

Conversely, people would be flipping out if the expectation was 3 feet of snow and or -65C temperatures to hit your area.

That said, I have trouble imagining anyone saying “just 6 inches of rain and 50 - 70 MPH sustained wind speeds”. The low end of tropical storms aren’t that bad but it covers a wide range.

Just to prove the point that it’s all about where you live and what you’re used to.

Both of your references are at the end of the scale, but not particularly unusual for areas I’ve lived in. It’s both a lot of snow and very cold, but it’s not that much more snow or that much colder than what most people have seen.

Such extreme weather is still a dangerous inconvenience even if it’s not that rare where you live.

And nowhere sees a full blown tropical storms or 3+ feet snowstorms more than a handful of time a year.

From Florida and have lived all over the state all my life. I've seen nasty hurricanes, but I've also seen nasty depressions that stall and wreak more havoc than a hurricane. There's nothing "just" about tropical storms.

As someone who grew up in Florida, there kinda is.

Tropical storm winds aren't enough to cause a problem most of the time. (Falling branches, or particularly weak trees)

Rain can be a problem, if the storm moves slowly.

I also grew up in Florida (I was in Miami for Andrew... fun times). A tropical storm is a significant weather event. It is especially the case for places that don't get this kind of weather. "Just" is completely inappropriate in the context of Hillary hitting California.

Florida tends not to flood due to the sandy soil and limestone. Its trees tend not to fall over (imported Banyans notwithstanding) because palms and pine don't present much canopy to the wind. Flooding is typically only something that happens in low-lying areas due to storm surge. Florida homes are built to withstand hurricane force winds (at least since Andrew). It has storm systems designed to handle a lot of water all at once.

California has clay soil in a lot of places. It doesn't absorb water quickly. It has different foliage that won't handle the wind as well. It has building codes for earthquakes, but probably not for significant wind events. I have no idea how much water the LA storm system can handle all at once.

I live in NC now and even here, tropical storms cause trouble because our soil doesn't drain well and the density of trees is a lot. Even just a bad thunderstorm last week knocked out the power for 100K homes.

The soil and flood events are going to be the gotcha from this. I was in LA at the beginning of the year for the unreasonably and torrentially rainy week. Definitely not a soil that takes well to rapid rain.

I know that California has been burying their power lines (for wildfires).

Not sure how widespread that currently is.

I, too, am from Fl. All my life. Complacency has no place in tropical wx.

California has its own challenges from lightning strikes and hydrology.

But in terms of wind, you'd get laughed out of any Gulf or Atlantic seaboard state for freaking out about a tropical storm.

If a residential structure can't survive tropical storm force winds, then code enforcement took a day off.

It's not a competition. Just as people who live in areas not known for earthquakes will see greater damage should one hit, people who don't normally see hurricanes will see greater damage should one hit (or a tropical storm). It's also about more than housing. The infrastructure isn't prepared to handle such weather either.

My point is that below category 3, you're going to have some power outages, debris cleanup, and mobile home damage.

TS-level wind will be handled by any well built structure.

The rainfall, on the other hand...

Sure there is. Tropical storms can be very weak. Slightly more rain and winds than normal.

I live within a 45 drive time of North Carolina’s Outer Banks. A tropical storm doesn’t even register as anything more than a summer storm here. Even a Category 1 hurricane isn’t really something that causes great concern in this area. Landfall at Category 2 or greater is where people start getting worried.

I really don’t mean to be flippant here, but I doubt anyone needs to be all that concerned about Hilary.

Complacency has no place in tropical wx.

If you actually read that list rather than let yourself be guided by the titles, only one of those (the 1858 one) may have made landfall as a hurricane (the reconstructed track has even it just missing landfall), and the only tropical cyclone known to have had its center over CA as a even a tropical storm was the one in 1939.

> Note, Hilary won’t be Hurricane by the time it hits California.

And it will be the first Tropical Storm over the state since 1939, and its not making a glancing blow to the coast like most tropical cyclones hitting California, but tracking straight up through central SoCal toward and potentially into Nevada, with tropical storm strength winds likely over the whole width of Southern California, massive rainfall, high flash flood risk in a stretch through Southern California up into Nevada, moderate flash flood risk to places as distant from the main track as Las Vegas and potential flooding impacts to and beyond the northern borders of California and Nevada, as well as east into Arizona and Utah.

Then the headline should be changed.

There's plenty of concern around global warming without exaggerating climate and/or weather events. Straying from the facts helps nobody except the news outlets.

Edit: technically, WaPo didn't misstate anything in the headline, but it's a bit deceptive. The HN headline is (currently) wrong, probably because the submitter was fooled by WaPo.

The rainfall estimates for Twentynine Palms and Death Valley are crazy- I'm no expert but I expect this to change the area forever.

https://www.nhc.noaa.gov/refresh/graphics_ep4+shtml/204534.s...

https://www.dvidshub.net/news/451702/hurricane-hilary-impact...

> A storm with such severity has not occurred since 1939.

> Anticipate substantial rainfall from heavy rain bands, with precipitation ranging between 8 to 15 inches

Why would it change it forever, Death Valley gets torrential rains and flash floods a few times a year already.

Death Valley had a 1,000 year rain event last August:

> The 1.46 inches of rain recorded at Furnace Creek is still preliminary data, and mere drops away from the all-time record of 1.47 inches. The rain caused widespread damage and closure of all park roads.

https://www.nps.gov/deva/learn/news/death-valley-experiences...

If Hillary is expected to drop 8-15 inches in Death Valley, that's going to be quite a bit more water.

I drove through 29 palms a month or so ago and half of the main roads around there is washed away. It was a split off Amboy road I think.

The Atacama Desert historically gets bursts of rainfall that cause the desert to briefly burst into vibrant bloom. It's still the Atacama Desert.

interestingly research on San Andreas fault and Salton sea was recently published in July noting of fill up relating to slip rate; https://doi.org/10.1038/s41586-023-06058-9

Another study published for September looks further into the history of slip rate and fill up; https://doi.org/10.1016/j.epsl.2023.118271

Very interesting. Any estimates on how much water the Salton Sea might gain from this storm? How would it compare to historical levels? (Including those used in the earthquake modeling)

no idea, was hoping someone more in the know of the field would comment. one thing id ponder too is.. the time frame... how long say for fill up to slippage? i just link cause i had come across the study from a news story month back and it just one of those weird things almost akin to simulation where its like "of course this brings a lot of rain to the area"... hopefully its not enough to do much in that grand scheme of things and just enough to help with drought conditions ie hoping salt lake gets some of that rain too.

So is this saying that the more water is in the salton sea, the more earthquakes could take place?

washington post article is probably more straightforward, to quote

"The team created a computer model that simulated how a full lake affected the fault. They found high water levels in Lake Cahuilla prompted activity along the fault in two aspects. First, the weight of the lake water caused the crust beneath it to bend, unlocking the plates so they don’t touch as much. The lake water also seeped into the cracks and pores in Earth’s crust beneath it, increasing the fluid pressure inside the fault and further unclasping the plates."

https://www.washingtonpost.com/climate-environment/2023/06/0...

* Sorry for formatting, not really my strength.

Thank you!

Slightly worried about fires starting. Sandy was tropical storm that hit an area that was unprepared, lots of flooding. Don't think so cal is going to handle that well. Along with the power companies being kind of shit... Good luck

Solar power production is already down by half from a typical summer day and the rain isn't really here yet. CAISO is forecasting substantially reduced supply capacity for Sunday. Luckily, they are also forecasting very little demand.

Is this not the anticipated reason our predecessors built all that infrastructure for channelizing and holding in the water all over LA?

No. It’s because it’s practically a desert and deserts have problems with flash flooding since the ground can’t soak up water effectively. Throwing concrete on huge portions of the city also contributes to flooding issues.

My understanding is that the channels, especially channelizing the LA River, were done to handle floodwater from further inland in the watershed, especially the mountains in spring. Having to handle both incoming floodwaters and record-setting local rain is beyond their design specs.

https://archive.is/xrKNt

I always thought storms in the pacific were called ‘cyclones’.

North/South hemisphere is the distinction there.

It's a bit more nuanced than that:

https://gpm.nasa.gov/resources/faq/what-difference-between-t...

> The terms "hurricane" and "typhoon" are regional names for tropical cyclones.

...

> Over the Atlantic and East Pacific, tropical cyclones are commonly called "hurricanes." The common term is "typhoon" for a tropical cyclone that forms in the West Pacific. Tropical cyclones are called just "cyclones" in the Indian Ocean and near Australia.

So basically they're all cyclones, but depending on where they originate they might get more specific terms as well.

They are all tropical cyclones.

In the North Atlantic and Northeastern Pacific, the strongest tropical cyclones are called “hurricanes”, while weaker ones (at least in the US) are called “tropical storms” and “tropical depressions”, in declining order of strength.

In the Northwestern Pacific, the strongest are called “typhoons”.

Elsewhere (South Pacific and Indian Ocean), they are just all called tropical cyclones or cyclonic storms, with additional adjectives denoting strength.

Technically they are all called tropical cyclones with the word hurricane being specific to the North Atlantic.

“Hurricane” is a word for a particular strength of tropical cyclone particular to the North Atlantic and Northeast Pacific (which is why Hilary, which we are discussing, is currently a hurricane, despite very much not being an Atlantic storm.)

I posted this in a comment but going to post it again at the top level. For anyone interested in discussing this, I highly recommend you read the NHC forecasters day 2 summary. Ignore the media, just go straight to the source.

This is very much unprecedented, despite many here posting that hurricane remnants hit CA all the time.

https://www.wpc.ncep.noaa.gov/qpf/ero.php?opt=curr&day=2

Here's the bit, buried towards the end:

The 19/12z NAEFS is indicating IVT values 19.1 sigmas above the mean; it should be noted that it is using a dataset that does not include the rash of tropical cyclones that impacted the Southwest in the 1970's, so this value is likely a bit too high. Even assuming a non-standard distribution and standard deviations half as large, this is extreme. There is a very real potential for 3" amounts in an hour in this environment should sufficient instability be present. Even if instability was completely eroded, 0.5" an hour totals would be possible; heavy rain appears inevitable. The 00z Canadian Regional shows local amounts of towards 10", which would be exceeding rare for the region from a tropical cyclone, potentially unique for Nevada. The 100 year ARI is forecast to be exceeded. Some locations within this arid region are slated to get 1-2 years worth of rain in one day. If a 7"+ maximum materialized over Mount Charleston Sunday into early Monday, it would challenge Nevada's 24 hour rainfall record, set in 2004.

What's wild to me is that 1-3" of rain / hour is about our norm for any given storm (southern MO, where evey cloud is a microburst). Really helps put into perspective how little rain Cali is used to.

At least that part of California. It's a gigantic state and some areas see fairly significant seasonal rain. This storm, however, will impact a region that includes the Mojave Desert - the dryest place in North America.

IIRC, The excellent book Dreamt Land says 2/3 of California's precipitation falls in the northern 1/3 of the state. But it's the southern part with the ideal climate for agriculture. Hence the largest water movement system in history.

One interesting thing I learned while in Las Vegas during a major rain storm, a lot of the buildings leak like a sieve. Word was that heavy rain happens so rarely that leaks are rare to present themselves and thus hard to discover and hard to troubleshoot.

Same with your windshield wipers. You use them so infrequently, you don't notice the rubber disintegrated until the next time you need them.

I'm watching this storm with interest, but I'm a little bit skeptical due to all the extreme language that the NWS forecast used around the storm in January February of this year, which ended up being basically a nothing Burger.

What? The storms in January and February were a huge deal for California coastal regions. The president visited Santa Cruz county afterwards.

It depends on which ones you're talking about. I got hit pretty hard by the rain around New Years in late December and early January, so I was watching the forecasts fairly closely.

There's also the question of what constitutes a huge deal.

It was the later storms where the NWS is using far more extreme language that ended up being basically inconsequential

With all these once in a 100 year events happening in the past decade it makes you rethink just how chaotic the 1910s-1930s were.

Yeah climate change was really bad back then

September 28–October 1, 1932: The remnants of a hurricane brought four days of rain. Flash floods killed 15 people

I mean, shit happens?

https://en.wikipedia.org/wiki/List_of_California_hurricanes

That was particularly bad for a few reasons 1. There wasn't any weather station in the areas so people didn't know the storm was coming. 2. The LA area didn't have nearly as much of the US army corp of engineers' flood control systems it has today.

LA nowadays has an incredibly robust flood control system. I wouldn't be surprised if this ends up being a bad thunderstorm and mostly a nothing burger.

Forecasting can make a huge difference.

When a hurricane practically wiped Galveston off the map in 1900, US weather forecasting capabilities were extremely limited. [1] On a much smaller scale, there was the Blizzard of '78 which basically shut down Boston for a week and stuck many drivers on Route 128 from which they had to be laboriously evacuated. Quite a few people were stuck in their offices for a week--all in part because the storm pretty much caught everyone by surprise.[2]

[1] https://en.wikipedia.org/wiki/1900_Galveston_hurricane [2] https://en.wikipedia.org/wiki/Northeastern_United_States_bli...

Mudslides are upstream of flood control systems and likely the biggest threat. Similarly local flooding can cause a great deal of damage without being part of a stream system.

“Remnants of” Hurricane Ida killed 44 people in the NYC area in 2021, this is expected to still qualify as a tropical storm when it makes landfall.

1939, when there was a tropical storm track that actually ran through Southern California, is probably a better comparator (but, both general and, because of forecasting, specific preparedness should be much better this time – the existence of a Southern California forecast office, after all, was a direct response to that storm.)

Track looks much farther inland: the 1939 storm hit Long Beach, the track for this is predicted to run over what looks like about the Imperial Valley, and up north toward (and potentially still with tropical storm winds into parts of) Nevada. Less populated areas directly in the track, but pretty much the whole width of Southern California is potentially going to get tropical storm strength winds, as well as whatever rains this brings, which are the real problem.

The flash flood risk maps are…quite extensive. [0]

https://www.nhc.noaa.gov/refresh/graphics_ep4+shtml/204534.s...

When you're rolling thousands of dice on phenomena that only happen once every hundred years, you'll get a lot of hits each decade.

When the planet is this hot, the dice are loaded.

Probably more that observation and promotion is 1000x better than 100 years vs planet warming. 100 years ago i would have no idea any of these things happened because they didn't directly affect me and the threshold for reporting it outside the affected area was dramatically higher due to cost constraints.

It's both. The answer is both. These storms are becoming more frequent and more powerful, and the public is more aware of them.

That's usually what "probably more that..." means. The post I was responding to proposed one reason and I responded with the correct answer that it is probably more that reporting is quite a lot better now. If I was negating their answer I would have said "No, that is wrong, this is why...." Even in the last 40 years my answer is correct because people's exposure to this has increased leaps and bounds faster due to reporting than it has due to actual events happening. Hell, even in the 30 or so years I personally remember this is true. My local climate has barely changed while my exposure to news about climate disasters has exploded.

I feel like the science behind West Coast weather phenomena is dubious, if only because the West Coast US has basically no historical record.

There probably were a number of extreme weather events that hit CA before the 19th century. In fact if you delve into it, there are a number of legends passed down from the indigenous peoples describing huge fires and unbelievable rain storms that flooded the whole of the central valley. 40M of people now live in a place where we have literally no idea what kind of weird one-off weather events hit every 100-200 years.

> I feel like the science behind West Coast weather phenomena is dubious, if only because the West Coast US has basically no historical record.

There’s not a separate science of “West Coast weather phenomena”.

> There probably were a number of extreme weather events that hit CA before the 19th century.

Doubtless. No one would be surprised by this.

> In fact if you delve into it, there are a number of legends passed down from the indigenous peoples describing huge fires and unbelievable rain storms that flooded the whole of the central valley.

Huge fires are clearly things that can happen in California. Rain storms flooding the whole Central Valley aren’t as extreme as, say, over-a-month rain storms producing flooding everywhere on earth, as legends go, but have similar plausibility problems in that (1) they would leave material evidence which would have been found, and (2) the very same absence of a large-scale community with detailed records and communications that lets you say “the West Coast US has basically no historical record” means that the source of any such legend would necessarily have to be really free extrapolation from a much narrower observation.

we've had several tropical storms in the last few decades. This is media overhype and climate scaring. I learned how to ride my bike as a child during tropical storm nora.

I blame poor forest management.

You forgot the /s

and the public school system

It is Disney's fault. The whole Florida thing is just a distraction. In fact, the hurricane might have come from Florida.

Disney experiences a setback in Florida and now hurricanes hit California? I think you’re on to something.

Disney is a cover story for the high-tech survivors of Atlantis who have lived among us for thousands of years hiding their weather controlling technology from us. They're causing global warming now so that the seas evaporate and their old city will re-emerge from the cities, along with ancient R'lyeh which they will visit to make sacrifices to the Great Old One, Dread Cthulhu, in the hopes that He will eat them first and release them from this curse.

or. something. Aliens.

As someone in Socal, not really concerned. The atmospheric rivers last year were far more terrifying. We had a ton of snowpack, and if they had come along just a little bit later in the year we could have had an Arkstorm scenario.

Like a lot of weather stories, this is overblown. It won't be a hurricane by the time it gets to California, and remnants of hurricanes/cyclones are not infrequent.

https://en.wikipedia.org/wiki/List_of_California_hurricanes

For anyone in CA or Nevada reading this misguided comment, please read the latest update from the forecasters at NHC:

https://www.wpc.ncep.noaa.gov/qpf/ero.php?opt=curr&day=2

Teaser: "The 19/12z NAEFS is indicating IVT values 19.1 sigmas above the mean;"

Mean for this time of year?

.1" is average rainfall for the whole month of August for Los Angeles, so if they get 3" today, it is both a massive 30x the month in a day, and also nothing to panic about.

3" of rain in hour - will cause flooding and damage, but is not a rare event.

https://tscrestoration.com/tscnw/wp-content/uploads/2015/10/...

Serious question, overblown or not? CEnter has passed San Diego and they got .97" of rain (SD Airport measurement). Riverside 1.4". LAX 1.27", Long Beach 1.56".

This was fear mongering: "The 19/12z NAEFS is indicating IVT values 19.1 sigmas above the mean;"

Those have “Remnants of …” the concern is this will still be a full blown tropical storm when it makes landfall.

“Remnants of” Hurricane Ida caused severe flooding in NYC killing 44 in the area, tropical storms are much worse. https://www.reuters.com/world/us/new-york-city-mayor-declare...

So? Tropical storms kill also. It’s the rain and flooding more so than the wind.

It isn't that it isn't bad, it is that it is not a rare event.

As someone who has lived through many hurricanes and tropical storms, the tropical storms are often surprisingly bad. They can dump even more water due to being slow-moving and sitting in the same spot for much longer.

If you’re in an area that is unused to this sort of storm, you’d better take it seriously. It may not end up being a severe weather event, but I wouldn’t bet my life on it.

It isn’t the wind. Is the water. Wind might be a problem only if the storm tracks east of the coast thus causing storm surge. At this point it’s unlikely.

Also: read NHC discussions instead of anons on the internet.

Look what happened, a lot of rain, but not an outlier 1 in 100 year event.

> Prediction is very difficult, especially if it’s about the future

NHC is good at their jobs. US cities thankfully have been spared. Let's wait for the desert/mountain areas.

NHC was solid with their rain prediction:

Los Angeles and San Diego are both expected to see about 2 to 3 inches of rain. Substantially more rain — 4 to 7 inches or more — is probable in the mountains to the east of Los Angeles and San Diego.

What got screwed up was translating that into "OMG HAIR ON FIRE", because that level of rain happens every few years, and while it can cause damage, it is not that big a deal. It is rare in summer, but not rare in Southern California.

https://www.cnn.com/2023/08/19/weather/hurricane-hilary-cali... (updated 2 hours later than the WP article)

The hurricane weakened from a very dangerous Category 4 to a Category 3 storm on Saturday, according to the National Hurricane Center. [...]

Hilary is expected to continue to weaken as it moves north-northwestward through cooler waters toward Southern California.

Reply on news.ycombinator.com