Heavy rain caused by the El Nino weather phenomenon drenched California Wednesday, but it will be nowhere near enough to reverse a historic drought.

The US National Weather Service issued warnings of storms and floods in the counties of Los Angeles and Ventura, home to nearly 11 million people in total.

The first major El Nino storm of the season battered southern California on Tuesday, bringing heavy rain to the drought-stricken region and causing flooding and mudslides in some areas.

Mudslides damaged two homes in Pasadena, east of Los Angeles, but there were no injuries, the Los Angeles Times said.

There was also heavy snowfall in the mountains of the Sierra Nevada, but that will not be enough to mitigate the effects of California's long dry spell.

"We need four years like this to recover," Eric Garcetti, mayor of Los Angeles, said in an online chat with locals.

El Nino is the name given to a weather pattern associated with a sustained period of warming in the central and eastern tropical Pacific which can spark deadly and costly climate extremes.

Last month, the UN weather agency warned the phenomenon, triggered by a warming in sea surface temperatures in the Pacific Ocean, was the worst in more than 15 years.