Powerful storm expected to batter High Desert with rain, mountains with snow over weekend.

Weather experts are sounding the alarm as they expect a powerful, slow-moving storm to roll through Southern California, including the High Desert, over the weekend.

After an atmospheric river-fueled storm brought rain earlier this week, a more powerful version of the storm is expected to bring record rainfall Saturday night into Tuesday, according to the National Weather Service.

In the High Desert, most of the rain will fall Monday through Tuesday.

The National Weather Service is forecasting the four-day storm to bring up to 3 inches of rain to the High Desert, with close to 4 inches in places like the Cajon Pass and portions of Hesperia.

A flood watch will be in effect in portions of southwest California, including Apple Valley, Lucerne Valley, Hesperia and the San Bernardino Mountains.

Additionally, San Bernardino County, Riverside County, the Coachella Valley, Orange County Coastal Areas, Orange County near Banning, and the Santa Ana Mountains and foothills are under watch.

In San Bernardino County, sandbags are available at no cost to residents and businesses on a first-come, first-served basis at local fire stations. County Fire personnel may not be available at all times depending on emergency calls. For more information, visit sbcfire.org/sandbags.

County residents are urged to download the Ready SB County app through Google Play or the Apple App Store for alerts, evacuation routes and more. They also encourage residents to sign up for the Telephone Emergency Notification System Alerts at sbcfire.org/alertwarning.

San Bernardino Mountains could get heavy snow

In the San Bernardino Mountains, heavy snow is expected from Sunday to Monday, beginning above 7,000 feet, and then dropping to the 6,000-foot level.

Caltrans District 8 reported Thursday that chain control is already present on Highway 8 from Stanfield Cutoff in Big Bear to the northwest of Running Springs.

Travelers should expect chain control throughout all of the mountain communities during and after the storm.

San Bernardino County officials are also urging residents and visitors to refrain from snowplay on roads, which creates unsafe conditions.

Storm will hit hardest east of the High Desert

The bulk of the storm is expected east of the High Desert, in places like the Los Angeles metro area, and portions of Santa Barbara, Ventura, and Kern, counties, which could get 3 to 6 inches of rain and 6 to 10 inches in higher elevations.

The projected storm could bring life-threatening flooding, mud and rock slides, damaging winds, downed trees, power outages and the flooding of rivers and streets in those areas.

The National Weather Service in Los Angeles on Friday stated that communities near or in the south-facing mountains in Southern California would need to start preparing for possible evacuations.

Strong winds of 30 to 50 mph are expected in parts of L.A. County, with 60 to 90 mph in higher mountain areas.

Gov. Gavin Newsom announced the mobilization of more than 8,000 people to assist with storm preparation and recovery around California, including swift water rescue teams and urban search and rescue crews. The California National Guard is also on standby to assist communities in need.

Daily Press reporter Rene Ray De La Cruz may be reached at 760-951-6227 or RDeLaCruz@VVDailyPress.com. Follow him on Twitter @DP_ReneDeLaCruz  

This article originally appeared on Victorville Daily Press: Storm expected to batter High Desert San Bernardino Mountains