From fragile hillsides in Laurel Canyon to fire-denuded slopes in Santa Clarita to homeless people living in riverbeds, Los Angeles communities were bracing for the storm of the season Friday.

Heavy rainfall is expected in the Southland Friday, with showers likely through Saturday morning, as the region’s most powerful storm of the season strikes, forecasters said.

They warned of flash flooding and cascades of mud and debris down slopes stripped bare in wildfires.

“It’s going to be a messy day,” said Kate Hutton of the Los Angeles Emergency Management Department of Friday’s expected downpour. “If you can stay home, please do so.”

Friday’s rain is set to be heavy — up to an inch of rain per hour is expected — because the storm system is tapping into a so-called atmospheric river, sucking up warm moisture, forecasters said. Early estimates are that the region will receive 2 to 6 inches of rain in coastal and valley areas and 5 to 10 inches in the San Gabriel mountains and foothills.

• RELATED STORY: Epic rain expected in Southern California

National Weather Service meteorologist Kathy Hoxsie suggested commuters take evasive action.

“The thing to do is leave early with plenty of extra time,” Hoxsie advised. “Leave extra space between themselves and other cars. And just overall be real cautious.”

Hoxsie added that people who live in burn areas, such as Santa Clarita, should be even more cautious, but she was “pretty confident that people that live in those areas are already very aware.”

Los Angeles County Fire Department Capt. Mark Bernard, who commands Fire Station No. 123 off Sand Canyon Road in Santa Clarita, described residents as “very resilient,” in part because they had used 400 tons of sand for sandbags on their properties since August.

“They prepared for this before and do what they can to help themselves,” Bernard said. “They’ve been doing this since August because after the Sand fire there was the potential for mud and debris flow.”

The Sand Fire burned 41,432 acres after it began July 22 near Sand Canyon Road along the northbound 14 Freeway and was fully contained Aug. 3. The fire destroyed 18 homes, killed one man and forced the evacuation of 20,000 people.

An evacuation of residents in the burn areas was ordered in late January because of rain.

• RELATED STORY: Santa Clarita family picks up the pieces after storm ravages remote canyon home

“With our resources and training and skill level, this will be something we’re prepared for, and we have contingency plans in place and the manpower and equipment to save lives and property,” Bernard said.

Late Thursday, the Los Angeles County Public Works Department announced it would close public access to two road segments “based on the forecast of heavy rain, snow and icy road conditions.” Those closures are:

• Bouquet Canyon Road, between the gates just south of Big Oaks Lodge — approximately six miles south of Spunky Canyon Road — to the southern boundary of Angeles National Forest — two miles north of Vasquez Canyon Road — will be closed at 9 p.m. Thursday, Feb. 16.

• Angeles Forest Highway, between Aliso Canyon Road and Upper Big Tujunga Canyon Road, will close at 3 a.m. Friday, Feb. 17.

“The closures will remain in effect until the storm system has passed and the roads have been inspected,” county officials said in the press release.

L.A. County Supervisor Kathryn Barger said in a statement Thursday that the Sand fire burn area was at a heightened state of alert and homeowners could call a 24-hour toll-free hotline (800-675-4357) for recommendations to protect their property.

Moving from one mudslide area to another, Laurel Canyon Boulevard in the Hollywood Hills was completely open to all traffic as of Thursday afternoon. The area had been closed between Sunset Boulevard and Mulholland Drive after part of a home’s concrete foundation and patio slid down a rain-soaked hillside in January.

“We have crews monitoring, but we don’t anticipate any problems,” Hutton said of the area on Thursday. “But it’s always a possibility.”

• RELATED STORY: Laurel Canyon Boulevard reopens after road repairs following storms

Additionally, drivers should turn on their lights and beware of areas and intersections like the Sepulveda Basin in Sherman Oaks that can flood.

“Do not drive into these intersections because you can stall and be stranded,” said Los Angeles Police Department Valley Traffic Division Detective William Bustos.

The Los Angeles Homeless Services Authority also has been contacting homeless people and has extended hours for its winter shelter program to keep it open throughout the forecasted storm.

“It’s been pretty positive in terms of getting people in the shelters,” Hutton said.

The shelters will remain open through 7 a.m. Monday.

For more information about the program and shelter locations, click here

City News Service contributed to this report