Heavy Rain Due; Slide Fears Raised : Weather: Flash-flood warnings are issued for Laguna Beach and other Southland areas that were hit by the fall wildfires. Emergency crews on alert.

The season’s worst winter storm was expected to arrive this morning in the unnerving form of an inch or more of rain in areas of Orange County that can least afford it.

Flash-flood warnings were issued Sunday for all parts of Southern California that were hard hit by last fall’s wildfires--Laguna Beach included--where heavy rain could produce mudslides. “If we get an inch or more in these areas, it leads to the possibility of mudslides, flash-flooding and the debris flow of ash that was left behind by the fires,” said Dean Jones, a meteorologist at WeatherData in Wichita, Kan.

The possibility that this storm will be the worst so far this season, perhaps lasting until mid-afternoon Tuesday, triggered new fears that mudslides may further damage Laguna Beach, a city still struggling to rebuild.

“We’re looking at radar pictures and it’s looking fairly dense,” said Patrick Brennan, a Laguna Beach firefighter who was manning the city’s emergency command post Sunday night. “This is the storm that we’re most concerned with.”

Brennan was tracking the amount of rain that began arriving in Southern California late Sunday and figured that if it reached more than half an inch in one hour in an area, then Laguna Beach would embark on an all-out effort to move backhoes, graders, bulldozers and sandbags into place and residents out of their homes.

Those in the areas hardest hit by the fire--in Canyon Acres, along Park Avenue and in other nearby flood-plain areas--would be advised to move via the Police Department’s public address system. If necessary, Laguna Beach High School will serve as an emergency shelter for the American Red Cross, Brennan said.

Since the fall fires that burned hundreds of homes and left scores homeless, five winter storms have moved through Laguna. The worst storm up to now occurred shortly after the fires, causing rivers of mud that damaged homes and forced evacuations.

But by all indications, this storm has the potential to be much worse, according to meteorologists.

The Orange County Fire Department has teams on call to patrol the shores and inspect rivers and creeks that may swell, and has bulldozers, sandbags and crews at the ready, said Michele Palmer, communications supervisor for the department.

“Hopefully nothing will happen, but if it does, we’ll be ready,” Palmer said. “The first sign that we’ve got problems is if Laguna Canyon Road has to be closed. All we can do is hope, hope, hope that it doesn’t get bad.”

The storm began developing late Sunday some 500 miles from the coast, but had already dropped two inches of rain over San Francisco. The storm was moving south along the coastline. The rain was expected to be at its heaviest by this morning, leading to possible thunderstorms by this afternoon.

Temperatures were expected to drop markedly, with highs in the upper 50s and lower 60s today and lows in the upper 30s and lower 40s by Tuesday. The only good news is that after Tuesday, there’s not another storm in sight, said Jones of WeatherData, which supplies forecasts for The Times.

The rain of last week was a light sprinkling compared to what is expected today and Tuesday, he said, and any areas that had started to slide would only be worsened by this latest winter storm.

“It will be a messy situation if we get all the rain that we expect,” he said. “This is a lot stronger storm.”

Besides Laguna Beach, the National Weather Service issued flash-flood warnings for fire-ravaged hillsides throughout Southern California, including Topanga, Malibu and Altadena.

In anticipation of the storm, Los Angeles County firefighters have put more crews on duty and readied two sand-filled dump trucks for emergency sandbagging in mudslide-prone areas. The department’s swift-water rescue team has been placed on alert.

Quake victims in makeshift homes and tents are being urged to seek cover at Red Cross permanent shelters.

American Red Cross officials reported Sunday that they had closed the last two of what had been more than a dozen formal tent shelters after persuading the residents to move indoors. Red Cross spokeswoman Peggy Hinz said a handful of residents remaining at the large tent at Church on the Way in Van Nuys moved to indoor shelters, and about 100 from the Le Conte Junior High School shelter in Hollywood were taken by van to two indoor shelters.

Times staff writer John L. Mitchell contributed to this story.