As of 3 a.m. Monday, Aug. 21, there was 6.98 inches reported in Lake Palmdale, 4.26 inches reported at UCLA, and 3.29 inches reported in downtown L.A. The brunt of the storm, however, pounded the Los Angeles County area on Sunday, NWS meteorologist Lisa Phillips said, adding that showers will continue into Monday before the precipitation begins to taper off.
Los Angeles County Board of Supervisors Chair Janice Hahn signed an emergency declaration around midday Sunday, “signaling to state and federal agencies that Los Angeles County is ready to accept any assistance they can give,” she said. All Los Angeles County parks will remain closed through Monday, Aug. 21. Northern reaches of the county, including the Antelope Valley, experienced heavy rainfall from the storm along with runoff from the mountains. The Los Angeles County Sheriff’s Department reported a series of streets in Palmdale that were closed due to flooding, including:
- Sierra Highway between Pearblossom Highway and Avenue S;
- Avenue N between Sierra Highway and 10th Street West;
- Avenue Q at 35th Street East;
- Avenue P at 10th Street East;
- Avenue O at 30th Street West;
- Palmdale Boulevard at 30th Street East; and
- 30th Street East between Avenue S and Avenue R.
The message to residents across the area Sunday evening was to remain indoors and travel only if absolutely necessary. Mass transit systems were continuing to operate despite the rain. The storm known as Hilary resulted in the first tropical storm warning ever issued for Southern California. Before Sunday, a tropical storm had not made landfall in California since 1939.
Along with Hahn, Gov. Gavin Newsom issued a State of Emergency for the area. Hilary weakened from a hurricane to a tropical storm off the coast of Baja California early Sunday, but it still brought heavy rain, strong winds and fears of dangerous flooding to some areas, particularly the mountains and the Antelope Valley.
The storm made landfall near San Diego Sunday afternoon, prompting the National Weather Service to warn of “potentially historic amounts of rainfall” that was “expected to cause life-threatening to locally catastrophic flash, urban and arroyo flooding including landslides, mudslides, and debris flows through early Monday morning.”
A flood watch will remain in force across Los Angeles County until 8 a.m. Monday, Aug. 21. A series of flash flood warnings were issued over the course of the day as individual storm cells generated heavy sudden downpours.
“It’s critical that people, especially in LA/Ventura Counties, not let their guard down when rain rates drop off as there is still plenty of the storm left to go as we could easily see rain rates back up to an inch per hour or higher, especially in the mountains and Antelope Valley,” the NWS warned Sunday afternoon.
Forecasters reported that current models shows “rain coverage shrinking considerably on Monday, but still with some pockets of very heavy rain across LA Counties so the morning commute Monday may still be quite wet in some areas. These showers are expected to diminish through early afternoon but can’t rule out additional showers and thunderstorms, especially interior areas as clouds start to clear and we get some surface heating and increasing lift.” Most of the area was anticipated to receive between 1 and 4 inches of rain, with some mountain communities getting as much as 7 to 10 inches before the system moves through.
State and local officials said extra resources were in place, and utilities were also fully staffed to deal with any power outage or other emergencies. The Federal Emergency Management Agency said it was coordinating with California officials to provide support as needed. FEMA pre-positioned supplies at March Air Reserve Base in Riverside, and a FEMA Incident Management Assistance Team deployed to the California Office of Emergency Services and is prepared to assist with any requests for federal assistance. Additional teams were on standby for deployment if necessary, officials said.
California’s National Guard contingent has also “strategically pre-positioned resources throughout Southern California” as part of the statewide effort to prepare for the storm, officials said Saturday. Cal OES, through the California Fire and Rescue Mutual Aid System, deployed a total of more than 700 local government firefighters and support staff, as well as 15 Swift Water Rescue teams, two Urban Search and Rescue companies and three Regional Urban Search and Rescue task forces.
Los Angeles County officials said all county parks, buildings and facilities would be closed Sunday and Monday, including but not limited top picnic shelters, playgrounds, multi-use trails, restrooms, botanical gardens and arboretums, lakes and swim beaches, pools and aquatic centers, natural areas and nature centers, performance venues.
Officials at LAX advised travelers to check with their airlines for possible flight delays or cancellations. Hurricane safety tips and resources can viewed at noaa.gov/hurricane-prep. Adding to the mix, a strong earthquake centered in Ventura County shook most of Southern California on Sunday.
The magnitude-5.1 temblor struck at 2:41 p.m., about 4 miles southeast of Ojai, according to the U.S. Geological Survey. It was quickly followed by a series of aftershocks, the largest of them measuring a magnitude of 3.6. There were no immediate reports of injuries or damage.
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