Hope is fading for the four people who remained unaccounted for on Sunday, including the two-year-old daughter of the latest victim to be named.

Pinit Sutthithepa, 30, the mother of the missing toddler, was found dead at 3.45pm on Saturday, according to Santa Barbara County Sheriff's Office.  

The woman, nicknamed Oom, was found in Montecito - the affluent community that has been hardest hit by the deadly mudslides in Southern California.

At 6.30pm local time last night, the sheriff’s office said the current list of active missing person cases includes her daughter Lydia Sutthithepa, 2. 

The other missing people on the list were John ‘Jack’ Cantin, 17, Faviola Benitez Calderon, 28, and John ‘Jack’ Keating, 53. 

The update on missing people said: “Sheriff’s detectives are actively investigating these missing persons cases. “

But emergency officials warned the chances of finding more survivors in the ravaged landscape of hardened muck, boulders and other debris had waned considerably. 

The authorities said the search-and-rescue mission had shifted into a "search-and-recovery" effort, reflecting the diminished likelihood of finding anyone else alive.

The California Department of Fire and Forestry Protection (CAL FIRE) said: “Crews continue searching buildings and debris flows for trapped victims. 

“The large amounts of mud and debris are making access and progress challenging.”

The deadly mudslides struck the area in and around Montecito heavy rains unleashed torrents of mud down hillsides before dawn last Tuesday.

The mudslides came after a massive wildfire last month stripped hillsides bare of any vegetation to hold soils in place following a day of drenching showers.

There are also fears that further mudslides could strike again, prompting evacuations to prevent yet more death and destruction.  

Officials have ordered residents in most of the southeastern corner of Montecito to leave their homes for what was likely to be one or two weeks.