Why the new SoCal rain, snow storms could be so relentless, brutal and dangerous

Southern California will be hit with back-to-back winter storm systems that forecasters say will bring cold temperatures, high winds and snow at unusually low elevations.

Officials are still trying to build an accurate forecast. But they are warning of the possibility of severe and dangerous conditions.

The event is expected to be “a snowmaker of the likes we have not seen for many years,” said Andrew Rorke, senior forecaster with the National Weather Service office in Oxnard.

“The mountains certainly will see significant snowfall. The deserts and some of the highest inland valleys might even see a little bit of flurries, although accumulation is less likely,” added UCLA climate scientist Daniel Swain. “Really, the only place in California that’s going to see snow levels not get much below 2,000 feet is going to be right down near San Diego — but that’s still really low.”

Here is what to expect based on current forecasts:

The forecast

• Some areas could see snow as early as Wednesday at elevations as low as 1,500 feet.
• As of Tuesday afternoon, forecasts showed the Antelope Valley getting a dusting by late Wednesday, with some models suggesting that snow could fall across Santa Clarita and possibly on the highest peaks of the Santa Monica Mountains.
• In Los Angeles County’s higher mountains, including along the Grapevine, Wednesday could bring up to 4 inches of snow and significant traffic disruptions, weather officials warned. Later in the week, even more snowfall is expected to accumulate at higher elevations, up several feet in places like Big Bear or Lake Arrowhead.
• A blizzard warning is in effect in some L.A. and Ventura mountains.
• Coastal and valley areas of Southern California could see 1-3 inches of rain between Thursday and Friday.
• Temperatures will be 10-20 degrees below normal.
• Rains are expected to continue through Saturday.

Warnings

• The low snow levels could cause major driving problems, especially on major passes like Interstates 5 and 15. Mountain roads will also likely be impacted.
• The National Weather Service warned of “very dangerous” marine conditions along the coast. Storm gusts, rip currents and high surf are expected. “Dangerous conditions are capable of capsizing boats,” the NWS said.
• Rain in coastal and valley areas will increase driving hazards.
• Downed trees and power poles are another potential hazard.
• Whiteout conditions and increased chance of avalanches are possible in high elevations, which could see up to 7 feet of snow.

Cold weather health alert

• The Los Angeles County Department of Public Health on Tuesday issued a cold weather alert for the Antelope Valley, the Santa Clarita Valley and Mt. Wilson for Wednesday through Saturday, with temperatures expected to drop below freezing.
• Officials tell residents in these areas to seek shelter and public facilities if needed and to not use stoves, grills or ovens to heat homes because of the risk of carbon monoxide poisoning.

Safety tips

• Sign up for alerts and check often for updates. Sign up to receive alerts about emergencies. For the city of Los Angeles, sign up at Notify L.A. If you’re elsewhere in L.A. County, you can find your municipality’s alert system sign-up here. For other places, search “emergency alerts (your city or county).”
• Prepare as if the power might go out. Here is a complete list of what to do before, during and after a blackout.
• Heed evacuation orders. If you’re told to evacuate, go. Here’s what to pack for an evacuation.
• Stay safe on the road. Even after the rain is over, streets could still be flooded or closed by downed trees and other debris. Leave extra time to reach your destination and heed all road closures.
• Drive with caution. Check for closed roads and hazardous conditions.

Here are more tips:
California is being hit by another massive rainstorm. Here’s how to prepare and stay safe

‘Turn around, don’t drown’ and other survival tips for driving in heavy rain

This massive storm may mean blackouts. Here’s what to do before, during and after the power goes out

How to prepare and pack if you might need to evacuate

How to sign up for emergency alerts in Southern California