Snow, rain and hail are all expected to intensify over the Southland today as a powerful winter storm gives the region a taste of weather normally reserved for more eastern reaches of the country.
The California Highway Patrol has closed Interstate 5 through the Grapevine for heavy snow and dangerous driving conditions. The northbound I-5 is closed at Parker Road in Castaic. The southbound I-5 is closed at Grapevine. It is not known when the freeway will reopen. The CHP was escorting cars and vehicles through the Grapevine until about 1:30 a.m. Friday.
Record low temperatures for the day were reported in parts of Orange County by the National Weather Service. It was 57 in Anaheim on Thursday, breaking the record for the lowest maximum temperature of 58 set in 2022. It was 54 in Newport Beach, breaking the record of 55 set in 1946.
A rare blizzard warning will be in effect for Los Angeles County mountains from 4 a.m. Friday to 4 p.m. Saturday. National Weather Service forecasters said up to 5 feet of snow could accumulate in the mountains above 4,000 feet, accompanied by wind gusts topping 80 mph that will create “near zero visibility.” Higher elevations could see as much as 8 feet of snow, with accumulations of 6 to 12 inches possible at elevations between 2,000 and 4,000 feet, “including most major mountain passes.”
“Travel should be restricted to emergencies only,” according to the NWS. “If you must travel, have a winter survival kit with you. If you get stranded, stay with your vehicle.”
According to the NWS Los Angeles office — which is based in Oxnard — the blizzard warning is the first issued in the area since 1989, when a warning was also issued for the L.A. County mountains.
Rain and hail fell on parts of Los Angeles and Orange counties Thursday, and the Hollywood Sign got a light dusting of snow. Small amounts of snow also fell along the coast in Venice.
By mid-morning Thursday, hail had been reported in locations including Pasadena and Long Beach, while light rain fell in many other areas. According to the NWS, most areas on Thursday saw precipitation of less than a half-inch.
While the snow level dropped as low as 1,500 feet Thursday, it will increase to at least 2,000 feet by late Friday morning.
“This system will bring a broad swath of moderate to locally heavy rain and snow (to) the area,” according to the NWS. “… Snow levels will fluctuate quite a bit as the southerly flow will raise levels to about 4,500 feet briefly on Friday afternoon. This could create a mixture of rain/snow at the I-5 Grapevine area before precipitation turns back to all snow Friday evening.”
Coastal and valley areas could get between 2 and 5 inches of rain during the storm by Saturday night, with 5 to 10 inches possible in the foothills. Forecasters said some areas could get rain falling at a rate of an inch per hour, particularly Friday afternoon and evening.
A flood watch will be in effect from Friday morning through Saturday afternoon for Los Angeles County beaches, the coastal region including downtown, the L.A. County mountains, Santa Monica Mountains and the San Fernando, Santa Clarita and San Gabriel valleys.
A flood watch will also be in effect in Orange County, covering inland areas and the Santa Ana Mountains and foothills.
In Duarte, city officials will implement a yellow alert in the Fish Fire burn area beginning at 11 a.m. Thursday. During the alert, Mel Canyon Road will be closed from Brookridge and Fish Canyon roads, and residents of the 25 homes in the area will be under parking restrictions and ordered to remove trash bins from the street. The trash pickup scheduled for Friday will be canceled and rescheduled for Monday, city officials said.
But snow will be the bigger story of the storm, with the low elevation snow level contributing to what could be “the largest amount of 24-48 hour snowfall seen in decades, likely rivaling the 1989 storm, for our Ventura and Los Angeles County mountains,” according to the NWS.
“Snowfall of this rate and amount could lead to damage to structures and trees with an immense threat of avalanches, especially in the eastern San Gabriel Mountains by Saturday,” forecasters said.
Mountain passes will also be impacted by snow, with 6 to 12 inches possible through the Grapevine section of the Golden State (5) Freeway.
“After the steady heavier precip starts to taper off Friday night, numerous showers with still a chance of thunderstorms are expected through Saturday evening,” according to the NWS. “Locally heavy downpours are possible, however, there will also be brief periods of sunshine in between showers.”
Temperatures will be in the 40s and 50s in most of the area, although they will drop into the 30s in the mountains and some valley areas, particularly at night, and into the 20s in the Antelope Valley.
High winds will make it feel even colder. Forecasters said strong winds will impact the entire region Friday and Friday night, strongest in the mountains and deserts. Gusts of 55 to 75 mph are anticipated in those areas, contributing to the blizzard-like conditions.
“Winds may drop off Saturday, so the blizzard warning may be downgraded early for some areas,” forecasters said. “Expect whiteout conditions at times within the blizzard warning, mainly above 3,500 to 4,500 feet in elevation. Significant blowing and drifting of snow combined with the whiteout conditions will make driving very difficult to impossible, including for rescue crews.
“The incredible amount of snow combined with the strong wind will lead to extreme avalanche conditions along steeper terrain and at lower elevations than we typically experience in southern California. The most significant threat for avalanches is typically within 24 hours of new snowfall. The heavy snowfall will increase risk of downed trees and power outages and can cause damage to roofs which have shallow slopes.”
