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Climate and Environment

Orange County Homes On Precipice Of Disaster As Record-Setting Rain Hits Southern California Hard

A row of apartment builds sits on the very edge of a cliff that is visibly eroding above Amtrak rail tracks following heavy rains.
Residents were evacuated from homes overlooking the Pacific Ocean coastline in Orange County.
(Patrick T. Fallon
AFP via Getty Images)
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The aftermath of Southern California's latest atmospheric river is playing out in dramatic fashion in Orange County, where several homes are at risk of sliding down an oceanside cliff in San Clemente. Those buildings were red-tagged Wednesday night by fire authorities — indicating they are unsafe to occupy.

As of Thursday morning, the site was still being assessed by building inspectors and geologists hired by the city, according to the OC Sheriff's Department. It's unclear if the hillside is still moving. Another atmospheric river is expected to hit mid next week, and could raise the possibility of further damage to the site.

The spectacle of teetering apartment buildings was foreshadowed by meteorologists who warned all week that mudslides had become increasingly likely amid record rainfall.

Enough rain fell Tuesday to overtake a record set more than 110 years ago in Santa Maria. And in Orange County, more than 4 inches fell in Oceanside Harbor on Wednesday — eight times the previous record.

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In most areas, the storm wrapped up by Wednesday afternoon, and a few lingering showers could bring additional snow to mountain areas above 6,500 feet.

Don't put away the galoshes though, especially if you're driving. Meteorologists caution that even after the rain ends, we could still see flooded roads and debris flow issues.

"We could still see some mudslides, landslides to areas that are kind of most vulnerable 'cause there's just been so much water over the last season for sure, but especially over the last week or two,” said Ryan Kittell from the National Weather Service.

Looking ahead to the weekend, there’s a 20% chance of light showers for Friday night.

OC homes on precipice of disaster

Across most of Southern California, the hazards have come in the form of flooded roads, swift water rescues and minor debris blocking highways.

However, in Orange County a perilous scenario presented itself Wednesday morning.

Four multi-family homes along the coast in San Clemente were evacuated as the hillside behind them has partially collapsed. Just on Tuesday, kids were swimming in a pool on one of the properties. By Wednesday, the hillside beneath said pool no longer exists.

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"The patio just decided to fall down," said Alex Heumann, one of the homeowners who was awoken abruptly by the sound at 8 a.m. "I heard a big boom this morning that sounded like a building falling."

After the collapse, Heumann said he and his pregnant wife could smell gas, and were evacuated not much later.

All families were evacuated safely and the buildings were first yellow tagged and then, late Wednesday, red tagged to indicate they are unsafe to occupy.

Later in the day, the site was walked by Orange County Supervisor Katrina Foley and a team from the County Fire Authority. Looking up at the damage from the base of the cliff, they came across geologist Jeff Hull.

Hull, not there in an official capacity, offered an off-the-cuff visual assessment to the group, saying that he was mostly concerned with the upper 20 to 30 feet of the bluffs, which appeared to be covered in sandy material.

Structural problems can arise for sandy hillsides when they're saturated with water. That additional moisture can compromise the ability of the individual particles to stick together, and add so much weight that the material can give out.

Meanwhile, another group of homes in nearby Newport Beach are threatened as well. Earlier in the month, the bluff behind one of them collapsed, leading to the evacuation and red tagging of multiple properties. There's major concern that the hillside could continue to break down, potentially bringing with it dozens of other houses in the neighborhood.

A local state of emergency was declared in OC on Tuesday by the county's Board of Supervisors, which allowed Gov. Gavin Newsom to add the area to the list of places throughout the state that'll receive emergency funding to help with storm damage.

Rainfall records set this week

The National Weather Service reported that several new records were set for the date:

  • LAX: 1.97 inches broke the old record of 0.43 inches set in 1982.
  • Santa Barbara Airport: 2.54 inches broke record of 1.36 inches set in 1952.
  • Santa Maria Airport: 1.63 inches broke the old record of 0.68 inches set in 1910.
  • Paso Robles Airport: 1.27 inches broke the old record of 0.75 inches set in 1958.
  • Camarillo Airport: 2.04 inches broke the old record of 1.46 inches set in 1930.
  • Long Beach Airport: 1.53 inches broke the old record of 0.63 inches set in 1982.

Downtown L.A. saw enough rain on Tuesday to make 2022-2023 its 14th wettest water year (starts Oct.1) recorded.
The totals for this storm will continue to increase slightly as it wraps up throughout the day.

Don't go swimming

The L.A. Department of Public Health is recommending that people stay out of the water until at least 10 a.m. on Friday because of runoff.

And the city of Long Beach is warning residents to stay away from local beaches following a sewage spill in the Los Angeles River. L.A. County public health officials reported approximately 18,000 gallons of sewage spilled into the river in the city of Paramount, triggered by heavy rainfall.

As of now, Long Beach has closed beaches west of the Belmont Pier while public health officials monitor the water quality. The white markers on this map indicate a water quality advisory is in effect at all county beaches.

About atmospheric rivers

This atmospheric river was shorter lived than others we've seen recently.

We make a big deal about them for a few reasons.

One is that, on average, they're responsible for roughly half of our precipitation each year. And just a handful of atmospheric rivers can be the difference between a wet year and another bleak, drought-ridden one.

The second reason is that because they can drop so much water, they're also some of our most destructive storms, causing billions of dollars of flood damage to states across the Western U.S.
An image that displays the science of an atmospheric river. "A flowing column of condensed water vapor in the atmosphere responsible for producing significant levels of rain and snow."
Atmospheric rivers are responsible for bringing substantial precipitation to California.
(National Oceanic and Atmospheric Administration

This storm was ranked as a 2-3 on a 5-point intensity scale.

The Atmospheric River Scale
  • • AR 1 (Weak): Primarily beneficial. For example, a Feb. 2, 2017 AR hit California, lasted 24 hours at the coast, and produced modest rainfall.

  • • AR 2 (Moderate): Mostly beneficial, but also somewhat hazardous. An atmospheric river on Nov. 19-20, 2016 hit Northern California, lasted 42 hours at the coast, and produced several inches of rain that helped replenish low reservoirs after a drought.

  • • AR 3 (Strong): Balance of beneficial and hazardous. An atmospheric river on Oct. 14-15, 2016 lasted 36 hours at the coast, produced 5-10 inches of rain that helped refill reservoirs after a drought, but also caused some rivers to rise to just below flood stage.

  • • AR 4 (Extreme): Mostly hazardous, but also beneficial. For example, an atmospheric river on Jan. 8-9, 2017 that persisted for 36 hours produced up to 14 inches of rain in the Sierra Nevada and caused at least a dozen rivers to reach flood stage.

  • • AR 5 (Exceptional): Primarily hazardous. For example, a Dec. 29 1996 to Jan. 2, 1997 atmospheric river lasted over 100 hours at the Central California coast. The associated heavy precipitation and runoff caused more than $1 billion in damages.

Driving in the rain

  • Roadway safety experts advised motorists to:

    • Check weather and road conditions all along your planned route
    • Slow down
    • Keep a wider-than-usual distance between your vehicle and the one in front
    • Don't drive through standing water — as little as 12 inches of rushing water can carry away most cars, and two feet can carry away SUVs and trucks.
    • Make sure tires are fully inflated
    • Check windshield wiper blades and replace if necessary

How to stay safe in high winds

Safety tips from Southern California Edison
    • Watch for traffic signals that may be out. Approach those intersections as four-way stops.
    • Make sure you have a battery-operated radio and flashlights. Check the batteries to make sure they are fresh. Use flashlights for lighting during a power outage; do not use candles because they may pose a significant fire hazard.
    • If you’re in a vehicle with a fallen power line on it, stay in the vehicle and remain calm until help arrives. It is OK to use your cellphone to call 911. If you must leave the vehicle, remember to exit away from downed power lines and exit by jumping from the vehicle and landing with both feet together. You must not touch the vehicle and the ground at the same time. Then proceed away from the vehicle by shuffling and not picking up your feet until you are several yards away. 
    • Water and electricity don’t mix. Water is an excellent conductor of electricity. Do not step in or enter any water that a downed power line may be touching.
    • Do not use any equipment inside that is designed for outdoor heating or cooking. Such equipment can emit carbon monoxide and other toxic gases.
    • If you use a generator, place it outdoors and plug individual appliances directly into it, using a heavy-duty extension cord. Connecting generators directly to household circuits creates “backfeed,” which is dangerous to repair crews.
    • Leave the doors of your refrigerator and freezer closed to keep food as fresh as possible. Place blocks of ice inside to help keep food cold. Check food carefully for signs of spoilage. 
    • Check on your neighbors to make sure everyone is safe.

Additional storm resources

What questions do you have about the weather we're experiencing?
A massive winter storm is hitting Southern California. We're here to answer your questions.

Corrected March 16, 2023 at 1:42 PM PDT
A previous version of this incorrectly stated that geologist Jeff Hull had been hired by the city of San Clemente to assess the condition of the bluffs. Hull was on the scene on Wednesday in an unofficial capacity.
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