LOS ANGELES (CNS) - A major storm is expected to begin dumping rain on the Southland Tuesday evening, continuing through Christmas and possibly into the weekend, prompting a series of evacuation warnings for residents near recent burn areas, most notably the Palisades and Eaton fires.

A flood watch will be in effect from Tuesday afternoon through Thursday evening for much of Los Angeles County, with mud and debris flows possible across foothill and mountain areas, including recent burn scars, according to the National Weather Service.

"In summary, Tuesday through Saturday looks to be an extended period of significant rainfall," according to the NWS. "By Saturday evening, rainfall totals will range from 4-8 inches across coastal and valley areas to 8- 12+ inches across the foothills and mountains. Please take the necessary protective actions as flooding and debris flow will be a major issue this upcoming week."

Los Angeles city and county officials issued a series of evacuation warnings in advance of the storm.

The city of Los Angeles issued warnings that will be in effect from 11 a.m. Tuesday through 11 p.m. Thursday for residents of Pacific Palisades and Mandeville Canyon near the Palisades Fire, and south of Runyon Canyon near the Sunset Fire area.

"The Los Angeles Police Department will go door-to-door to visit each high-risk home with evacuation orders," according to Los Angeles Fire Department spokeswoman Lyndsey Lantz.

Los Angeles County officials, meanwhile, issued evacuation warnings for residents near the Palisades, Eaton, Agua Dulce, Lidia, Franklin, Bridge, Canyon, Owen, Hurst and Kenneth fires. Those warnings will also begin at 11 a.m. Tuesday.

In addition to the rain, the NWS predicted "very strong winds" Tuesday night and Wednesday, with gusts up to 80 mph over the higher peaks in the mountains, and up to 40-50 mph across lower elevations.

The NWS said an "Atmospheric River that has been pointed towards northern California the last few days will shift south and take aim at SoCal" on Tuesday, with less than a half-inch of rain expected Tuesday evening before the heaviest part of the storm occurs after midnight Tuesday night into Wednesday.

"Hourly rain rates, especially in the upslope areas, should easily top one inch per hour during the peak of the storm on Wednesday," the NWS said. "The heaviest rain will be in the south-facing mountains, but very heavy rain, possibly close to an inch per hour, is possible at lower elevations as well and anyone in particularly vulnerable areas ... or any recent burn scars should start taking protective actions ASAP.

"There will almost certainly be numerous mudslides, severe flooding either from heavy rain or clogged storm drains, and possibly debris flows near recent burn scars," forecasters continued.

While the worst of the storm will likely be Wednesday, periods of rain, possibly heavy at times, are expected on Christmas Day. Moist south to southwest flow will continue to usher in sporadic showers to the area Friday and Saturday, though rain amounts by that time should be under a quarter inch per hour.

Snow is not expected to be a major factor with the storm, with levels dropping to around 7,000 feet Thursday and Friday.

The city of Los Angeles' Emergency Operations Center was activated Monday in anticipation of the storm and to help coordinate response efforts by the Emergency Management Department, police and fire departments and county Public Works officials.

"Los Angeles city personnel are preparing for the storm this holiday week," Mayor Karen Bass said in a statement. "First responders, public works crews, and utility personnel are ready to respond to potential impacts due to the weather. Angelenos planning to travel to spend time with family and loved ones this holiday week should use caution on the roads, plan ahead, and stay informed. Sign up for emergency alerts at NotifyLA.org."

According to the mayor's office, the Los Angeles Fire Department will have stepped-up staffing in place to respond to swift-water rescues or mud and debris flows. Crews from the Department of Water and Power, Street Services and L.A. Sanitation are also on standby.

Free sandbags are being offered at all fire stations throughout the city.

Tim Conway Jr