Another devastating storm that killed at least 29 persons in southern California and Mexican border towns was gone yesterday, but seaside residents in Malibu still contended with raging seas in front of them and mudslides in back.

Forecasters predicted high seas up to six feet that could still carve away foundation of expensive homes in the Malibu Colony owned by such celebrities as Linda Ronstadt and Burgess Meredith.

At least eight persons were reported dead in southern California and 20 more in Baja California, Mexico. At least five persons were missing. Also, a two-year-old boy drowned in a rain-swollen stream in northern California.

Martin Alexander Stamps, 2, drowned in a creek near his San Jose home Saturday. Sean Moore, 18, of Azusa, was missing and being sought in the rushing waters of the San Gabriel flood control channel after a canoe he was in capsized.

More than 600 homes in Los Angeles and Ventura counties were damaged by water and mud, many severely. Hardest hit were houses in the suburban San Fernando Valley and in Filmore.

The National Guard helped Malibu residents fight tides of 5.7 feet and swell up to eight feet. Seas destroyed the porch of Meredith's home and washed away eight feet of Ronstadt's property, although no damage was reported to her house.