It’s not every day that snow blocks roads near the city of Santa Barbara in Southern California or snowflakes fall on the mountain where the iconic Hollywood sign is located. These scenes are thanks to a powerful winter storm creating unusual snowstorm conditions in the southern part of the state.
The National Weather Service (NWS) office in San Diego issued its first ever blizzard warning, and the agency’s Los Angeles office issued its first blizzard warning since 1989.
A massive storm has already brought frigid conditions across the Pacific Northwest, with Portland having Wednesday the second snow day with 10.8 inches of snow on record. Snow, winds, and colder-than-normal conditions are spreading across northern California as the storm moves south. According to NWS’s San Francisco Bay Area office, downtown San Francisco recorded the lowest temperature of 39 degrees Fahrenheit for the first time since 2017, and snow closed roads in the Santa Cruz Mountains south of San Jose.
Winter storms are not uncommon in California and snow often falls on the southern peaks of the state, although snowfall is usually inches. But the storm is expected to bring heavy snowfall, says Ryan Kittell, a meteorologist at the NWS’s Los Angeles office. Alex Turdy, a meteorologist at the NWS’s San Diego office, said in his online briefing:
Several factors come together to make this such a notable event. First, the storm is sucking air out of Canada, so it’s very cold. This unusually cold air is why Thursday’s snow fell at surprisingly low levels in the hills around Los Angeles, dropping elevations to about 1,500 feet. California State Route 154, which runs inland from Santa Barbara, was closed Thursday due to unusually low levels of snow from the storm. Kittel says he cannot remember what ever happened. (Whether it was snow on Mount Lee, home of the Hollywood Sign, or another closely related type of frozen precipitation called hail is unknown, but both are highly unusual.)
Storms will also take advantage of what meteorologists call atmospheric rivers, streams of very moist air pushed out by strong winds. “Then we’ll just have more rain and snow,” says Samantha Connolly, a meteorologist at her NWS office in San Diego.
That means there’s enough snow in the mountainous areas for the storm’s gale force winds to “almost be a whiteout” in those areas, Connolly says. “Traveling in the mountains will be nearly impossible.” These are the conditions that describe a blizzard that the NWS classifies as heavy snow, winds greater than 35 per hour, and storms with visibility of less than 1/4 mile.
In addition to snow, heavy rains can fall rapidly in low-lying coastal areas and valleys. There is a potential risk of flooding as the ground often cannot absorb water fast enough. This can be a problem especially in urban areas. It means more paved surfaces and less exposed ground to absorb rain.
On a more positive note, snowfall could help ease California’s years of drought. increase. “Even if it snows, if it rains,” says Connolly, the drought will be alleviated.
