The rains will be light and intermittent, falling at rates of between 0.1 and 0.25 inches per hour, with isolated rainfalls of up to 0.75 inches per hours, forecasters said.

The long-sought precipitation will begin Saturday afternoon and last through Monday night, with a 15% to 25% chance of thunderstorm mixed in. Up to a foot of snow was expected In the higher elevations of the San Gabriels.

But even though the rains are more than welcome after the region was devastated by a series of fires that killed at least 28 people, burned 57,000 acres and destroyed more than 16,000 structures, the possibility that they could trigger mudslides and debris flows over “burn scar” areas was also part of the forecast.

The NWS predicted a 10% to 20% chance of “significant debris flow” in Los Angeles County over the weekend and into Monday — up from an earlier estimate of 5% to 10%.

Flash flood watches were posted for the most severely burned areas of the region including the cities of Warm Springs, Valencia, East Los Angeles, Pomona, El Monte, Malibu Bowl, Wrightwood, Mount Baldy, Mount Wilson, Malibu, Acton, The Angeles Crest Highway, Lake Castaic, Santa Clarita, Mill Creek, Pasadena, San Gabriel, Topanga, Newhall, and Pacific Palisades.

“This will be a long duration event w/rain spread out over many hours, so rain will generally be beneficial,” the Los Angeles office of the NWS said in an update. “However, issues in & near recent burn scars are possible. If you live near a burn scar, follow guidance from local authorities.”

The California Governor’s Office of Emergency Services said Saturday it is preparing for the possibility of floods.

“With thunderstorms and widespread rainfall in the forecast for Southern California, [Cal OES] has strategically prepositioned critical resources near burn scar areas,” the agency said in a statement. “Prepositioned resources include fire engines, hand crews, dozers, dispatchers, a swift water rescue team, one rescue task force and multiple helicopters in two counties — Los Angeles and Orange.”

The rains are coming after containment of each of the four major wildfires still burning in region were upgraded on Saturday, according to the California Department of Forestry and Fire Protection:

• The Hughes fire near San Diego was 87% contained as of 10:30 a.m. Saturday after burning more than 10,400 acres. Los Angeles county lifted evacuation orders for areas in and around Castaic Lake and the Sheriff’s Department exited the unified command for the blaze.
• The Laguna fire was 90% contained after burning about 83 acres and was 90% contained as of Saturday morning as evacuation orders for the Cal State Channel Islands and University Glen lifted, according to Cal Fire. No structures were damaged in the fire.
• The epic Palisades fire was 81% contained as of 10:30 a.m. Saturday after burning more than 23,400 acres. Eleven people were killed and nearly 7,800 structures were damaged or destroyed at the latest count. Most of the heavily fire-damaged areas remained under mandatory evacuation orders.
• The Eaton fire near Pasadena was 95% contained. It claimed 17 lives and burned more than 14,000 acres with nearly 10,500 structures damaged or destroyed. Mop up operations continued throughout the perimeter of the fire on Saturday, Cal Fire said.