California is currently experiencing a significantly wet winter, with several areas already reaching or surpassing their average rainfall totals for the entire season. This follows a drier period earlier in 2024 that contributed to firestorms in January.
Current Conditions and Upcoming Storm
A powerful storm system is forecasted to move into California this weekend, increasing the threat of additional flooding and mudslides. This system is expected to bring gusty winds and increased precipitation, particularly in areas previously affected by wildfires.
A cold front, originating from the northwest, is projected to reach the Los Angeles area by Saturday, delivering rain and high-elevation snow through Sunday. Rainfall in Los Angeles is anticipated to be less intense than a preceding storm that caused significant disruptions, while the Central Coast is expected to receive heavier precipitation. Another colder storm system is predicted to affect the region between Monday and Tuesday, potentially bringing isolated thunderstorms, heavy downpours, hail, and snow levels down to 5,000 feet.
Northern California is also expected to be significantly impacted by the weekend storm, with heavy rain posing risks of urban and roadway flooding, as well as rising rivers and streams. On Friday, king tides in Corte Madera, Marin County, resulted in localized flooding.
Hydrological Data and Records
The Los Angeles region has recorded above-average precipitation since the current rainy season commenced on October 1. Notable storm systems occurred over the Christmas and New Year's holidays. Data indicates that the rainfall in late 2024 contributed to California's substantial recovery from drought conditions, according to the U.S. Drought Monitor, preceding traditionally wet months.
The storm system that impacted the Rose Parade marked the first such occurrence since 2006 and resulted in multiple daily rainfall records being surpassed:
- Oxnard: 1.09 inches (exceeded 0.83 inches from 2006).
- Sanberg: 1.25 inches (exceeded 0.56 inches from 2006).
- Hollywood Burbank Airport: 1.32 inches (exceeded 0.35 inches from 2006).
- Long Beach Airport: 1.11 inches (exceeded 0.60 inches from 1982).
- Lancaster: 0.87 inches (exceeded 0.24 inches from 2006).
Impacts and Incidents
Thursday's rainfall led to flooding on the 5 Freeway in the San Fernando Valley, necessitating lane closures. In San Diego, a man and his daughter required rescue from a vehicle in rapidly moving water. In Orange County, a woman's body was recovered from the Santa Ana River in Fountain Valley; the circumstances of her entry into the water were not immediately clear. In Sherman Oaks, heavy rain caused mud and debris to flow down a hillside at a residential construction site; no injuries were reported, though two individuals were evacuated from a nearby home.
The wet winter conditions offer short-term protection against large fires, though the duration of this protection is dependent on future rainfall patterns.
Forecast Details
The weekend storm is predicted to bring 1 to 3 inches of rain to coastal and valley areas, and 3 to 6 inches to foothills and mountains. Rainfall rates are estimated between 0.25 to 0.5 inch per hour, with localized rates potentially reaching 1 inch per hour, particularly in Ventura County foothills and mountains, which could result in flooding and mudslides.
Snow levels are expected to remain above 6,500 feet, with a rain-snow mix possible down to 6,000 feet by Sunday night. Forecasts indicate 2 to 6 inches of snow above 7,500 feet, and up to 9 to 12 inches on the highest mountain peaks.
Wind advisories have been issued for higher-elevation areas of Ventura and Santa Barbara county mountains, interior San Luis Obispo County, and the Santa Lucia Mountains. These advisories are effective from Friday afternoon through Saturday evening and may be extended to the Central Coast. Wind gusts are anticipated to be strong enough to potentially dislodge trees, especially in the Santa Lucia range, given the already saturated soil conditions from previous storms.
Public Health Advisories
The Los Angeles County Department of Public Health has advised the public to avoid ocean water at beaches due to elevated bacteria levels caused by the rain. This advisory is in effect until at least 4 p.m. Monday, with potential for extension.
Long-term Outlook
The current water year, spanning from October 1 to December 31, ranks among the top nine wettest for all official climate locations tracked by the weather service. Oxnard and Santa Barbara have experienced their wettest starts to the water year on record.
Downtown Los Angeles has received 11.64 inches of rain, which is approximately 82% of its normal rainfall for the entire water year (October 1 to September 30). Sanberg, in northwest Los Angeles County mountains, has recorded its wettest start to the water year since 1934, with over 16 inches of rain through Wednesday, exceeding its typical annual average of 13.14 inches.
Following this storm cycle, a period of dry weather, potentially lasting up to two weeks, is projected.