LOS ANGELES — Forget, for now, that "polar bear" ocean swim. Public health officials have issued an ocean water quality alert for all Los Angeles County beaches.

In a notice issued Thursday, the Los Angeles County Department of Public Health said the advisory will be in effect until at least 4 p.m. Monday because of increased bacteria levels. Officials said the advisory could be extended if it rains more.

"Bacteria levels can increase significantly during and after rainstorms, as contaminants within the runoff enters the ocean," the department said.

Once that water reaches the ocean, it can lead to elevated bacteria levels that can cause illness, the advisory said, especially in children and the elderly.

The advisory came on the heels of a rare Jan. 1 rainstorm that drenched Southern California and rained on the Rose Parade for the first time since 2006. The storm also triggered slides and major road closures across Los Angeles as well as swift water rescues in San Diego.

Flooding of the 5 Freeway in the San Fernando Valley prompted Caltrans to shut down all lanes between Tuxford Street and Lankershim Boulevard for several hours. A mudslide closed Big Tujunga Canyon Road in Angeles National Forest between the Angeles Forest Highway and Vogel Flat Road, marking the latest county road closure due to flooding and slides since Dec. 24.

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