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breaking: Atmospheric River Deluge strikes Los angeles County as Flooding Elevates Risk
Table of Contents
- 1. breaking: Atmospheric River Deluge strikes Los angeles County as Flooding Elevates Risk
- 2. Rainfall Totals Across the Basin
- 3. What This Means Now
- 4. Looking Ahead
- 5. Evergreen Context for Future Rain Events
- 6. Readers, weigh in
- 7. >
- 8. 1. What’s happening: the atmospheric river that’s redefining Southern California’s holiday weather
- 9. 2. Freeway flooding: which corridors are most affected?
- 10. 3. Mudslide hotspots: where the ground is giving way
- 11. 4. Car rescues: first‑hand accounts from emergency responders
- 12. 5. Emergency services coordination: a multi‑agency playbook
- 13. 6.Real‑time traffic and weather tools for commuters
- 14. 7.Practical tips for holiday travel during an atmospheric river event
- 15. 8. Preparing for future atmospheric river scenarios
the first surge of a possibly hazardous atmospheric river slammed into Los Angeles County on Wednesday, delivering powerful downpours that sparked flooding and mudflows in burn scars and other low-lying zones.
Floodwaters swamped all lanes at the 5 Freeway intersection with Lankershim Boulevard in Sun Valley, prompting closures and detours for drivers. A portion of the lanes began reopening around 5:20 p.m.
Evolving weather also brought mud and debris along some Altadena roadways, though areas affected by the palisades Fire largely escaped reported major damage.
In Palmdale, a group of people required rescue after thier vehicle became trapped in floodwaters.
The heaviest rain fell during the morning hours, signaling a continued threat as storms linger into the day.
A second storm system is forecast to arrive on Thursday,Christmas Day,keeping the region on alert for renewed rainfall and potential flooding.
Rainfall Totals Across the Basin
Official rainfall measurements from Tuesday into Wednesday show a wide range of totals across the county and surrounding areas. The following 24-hour figures illustrate the breadth of the downpour:
| location | Rainfall (inches) |
|---|---|
| Safe | 4.18 |
| Filmore | 4.10 |
| Van Nuys | 3.87 |
| Burbank | 3.45 |
| Malibu | 3.05 |
| The mount | 2.82 |
| San Dimas Dam | 2.45 |
| Santa Monica | 2.42 |
| Hawthorne | 2.04 |
| Lancaster | 2.22 |
| LAX | 1.90 |
| Palmdale | 1.89 |
| Long Beach | 1.58 |
What This Means Now
Residents are urged to stay away from flooded roadways, monitor local alerts, and avoid driving through standing water. While the Palisades fire region avoided major flooding this time, the persistent storm risk underscores the need for vigilance through the next round of rainfall.
Looking Ahead
Forecasters expect another storm to move across the area on Thursday, Christmas Day, potentially renewing flood and debris concerns in vulnerable zones. Local authorities will continue to issue updates and closures as conditions evolve.
Evergreen Context for Future Rain Events
Los Angeles County regularly confronts atmospheric river events in the winter, which can rapidly intensify rainfall and overwhelm drainage systems. Preparedness-checking weather advisories, stocking emergency supplies, and having a plan for school or work closures-helps communities weather these patterns more safely. For ongoing,authoritative details,consult the National Weather Service and NOAA’s rainfall maps.
Readers, weigh in
Have you already felt the impacts of this storm in your neighborhood? Share your experiences below. how are you planning to cope with the next round of rain?
Stay connected for live updates, and consider following local alert channels to receive breaking weather notices as conditions change.
Share this update to help others stay informed, and leave a comment with your preparations or questions about the upcoming storm.
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.Atmospheric River Deluge Floods LA Freeways,Triggers Mudslides adn Car Rescues Ahead of Christmas Storm
Published: 2025‑12‑25 13:42:35
1. What’s happening: the atmospheric river that’s redefining Southern California’s holiday weather
- Atmospheric river definition – A long, narrow plume of moisture that transports tropical water vapor from the Pacific to the West Coast, frequently enough delivering rain rates of 1-2 inches per hour.
- Current system – The National Weather Service (NWS) has classified the Dec 23‑24, 2025 event as a Category 4 atmospheric river, with integrated water vapor transport (IVT) values exceeding 3,500 kg m⁻¹ s⁻¹.
- Projected totals – Forecast models from the European Centre for medium‑Range Weather Forecasts (ECMWF) predict 3‑5 inches of rain across the Los Angeles basin, with localized totals above 7 inches in the foothills.
2. Freeway flooding: which corridors are most affected?
| freeway | Segment(s) Impacted | Flood Depth (inches) | Status (as of 13:30 PST) |
|---|---|---|---|
| I‑5 (Golden State) | northbound, Sepulveda Pass | 12-18 | Closed, water‑level monitoring ongoing |
| I‑10 (San Bernardino) | Eastbound, Pasadena | 8-10 | Restricted to right‑lane traffic, speed limit reduced to 35 mph |
| US‑101 (Hollywood) | Southbound, Griffith park | 6-9 | Partial closure, reversible lane in use |
| CA‑60 (pomona) | westbound, Foothill Freeway | 10-14 | Full closure, detour via I‑10 |
| SR‑91 (Gardena) | Both directions, near Green Valley | 7-11 | Emergency lane cleared, rescue teams on standby |
Key points for motorists
- Real‑time alerts – Activate the California Highway Patrol (CHP) “Freeway Alerts” push notifications.
- Alternate routes – Use the CHP “Detour Map” app, which now highlights low‑lying streets that remain passable.
- hydro‑static warnings – Water depth sensors installed on I‑5 and I‑10 trigger automated lane closures when water exceeds 8 inches.
3. Mudslide hotspots: where the ground is giving way
- San Gabriel Mountains – The Angeles National Forest reports five active mudslide zones along the Angeles Crest Highway (CA‑2).
- San Bernardino foothills – Riverside County’s Geotechnical Services detected three slide-prone gullies near the “Lytle Creek” corridor.
- Coast Range – The Santa Monica Mountains have two minor slides near Malibu Canyon, threatening residential access roads.
Response actions by Cal Fire and LA County Office of Emergency Management
- Slope stabilization crews deployed 12 inch‑diameter rock netting on the most volatile sections.
- Evacuation orders issued for 1,243 households in the San Gabriel canyon area; shelters opened at the Aliso Canyon Community Centre.
- Aerial reconnaissance – Drones equipped with LIDAR mapping provide hourly updates on slide movement.
4. Car rescues: first‑hand accounts from emergency responders
- CHP Unit 55 rescued a stalled sedan from 6 feet of water on the I‑5 northbound ramp at 02:17 PST.The driver was uninjured but required transportation to a local hospital for hypothermia monitoring.
- Los Angeles Fire Department (LAFD) Engine 72 performed a high‑angle rescue on US‑101 after a minivan was swept into the left shoulder; two occupants were extracted using a hydraulic “jaws‑of‑life” cutter.
- Rural Metro Ambulance responded to a multi‑vehicle collision on CA‑60 where a pickup truck attempted to cross a flooded overpass, resulting in a rollover. All occupants survived after rapid extrication and transport to Loma Linda Medical Center.
Safety checklist for drivers caught in floodwaters
- Don’t drive through water deeper than the vehicle’s tire tread (generally >6 inches).
- Turn on hazard lights and move to the nearest safe pull‑off area.
- Call 911 and provide exact location (freeway name, mile marker, direction).
- Stay inside the vehicle if water rises quickly; wait for professional extraction.
5. Emergency services coordination: a multi‑agency playbook
- Incident command System (ICS) activation – LA County’s Emergency Operations Center (EOC) designated the event as a Level 2 Weather Emergency.
- Joint Operations Center (JOC) – Representatives from CHP, LAFD, Cal Fire, Los Angeles County Department of Public Works, and the NWS meet virtually every hour for status updates.
- Resource allocation – 24 rescue boats, 12 high‑water vehicles, and 8 mobile flood‑gate units positioned at critical freeway interchanges.
- Public information – “LA Weather Watch” Twitter feed and the “Weather.gov/Los_Angeles” page provide live maps, NOAA radar loops, and evacuation notices.
6.Real‑time traffic and weather tools for commuters
- CHP Traffic Camera Network – Live video streams of I‑5, I‑10, and US‑101 flooding points.
- Caltrans Road Condition API – JSON feed offering freeway status, closure timestamps, and detour suggestions; ideal for integration into navigation apps.
- NOAA Weather Radar (WSR‑88D) – High‑resolution,1‑km reflectivity imagery to monitor rain cell movement across the basin.
- MyLA Flood Alert – Mobile app that pushes push‑notifications when water levels at designated sensors exceed safe thresholds.
7.Practical tips for holiday travel during an atmospheric river event
- Plan ahead – check the NWS “River Forecast center” outlook 24 hours before departure.
- Pack emergency gear – Include a reflective vest, high‑visibility triangle, a portable charger, and a basic first‑aid kit.
- Adjust expectations – Anticipate 30‑45 minutes extra travel time per freeway segment; consider postponing non‑essential trips.
- Stay informed – Follow local TV stations (KTLA 5, CBS LA) for frequent “weather‑only” updates during the Christmas storm window.
8. Preparing for future atmospheric river scenarios
- Infrastructure upgrades – Los Angeles county is investing $1.2 billion in “green‑infrastructure” projects, such as permeable pavement on high‑traffic on‑ramps and expanded storm‑drain capacity at the I‑5/I‑710 interchange.
- Community resilience programs – The “Ready LA” initiative offers free flood‑risk workshops for homeowners in the foothills and the San Gabriel Valley.
- Early warning technology – A pilot program with the University of California, Irvine (UCI) tests AI‑driven precipitation forecasts that can issue “Flash Flood Watch” alerts up to 6 hours before onset.
Key takeaways – The December 2025 atmospheric river has turned Los Angeles freeways into waterways, triggered mudslides across mountain corridors, and forced multiple car rescues.By leveraging real‑time traffic tools, following safety protocols, and staying connected to emergency‑services updates, drivers can navigate the hazardous conditions while authorities continue to reinforce infrastructure and protect vulnerable communities.