Flash flooding, evacuations as torrential rains pound Los Angeles area

Torrential rains swept across Southern California on December 24, triggering widespread flash flooding as authorities urged motorists to stay off the roads and ordered evacuations for residents living below wildfire-scarred hillsides and canyons, according to foreign media reports.

The deluge was driven by the region’s latest atmospheric river — a vast plume of dense moisture drawn from the Pacific Ocean and pushed inland over the greater Los Angeles area.

In some locations, rainfall rates reached an inch (2.54 centimetres) or more per hour, rapidly overwhelming drainage systems and inundating streets.

The US National Weather Service said the Christmas Eve storm was expected to persist through December 26, creating hazardous driving conditions during what is typically a busy holiday travel period. Forecasters warned that “life-threatening” conditions would continue through Christmas Day across Southern California, where flash flooding was already underway.

A flash-flood warning was issued for much of Los Angeles County until 6 p.m. PST, with authorities urging motorists not to travel unless evacuating a flood-prone area or complying with an evacuation order. Los Angeles city officials specifically called on residents to heed evacuation notices affecting about 130 homes deemed particularly vulnerable to mudslides and debris flows in areas where last year’s wildfires devastated the Pacific Palisades community.

The heavy rainfall was accompanied by strong, gusty winds that forecasters warned could topple trees and knock down power lines. At higher elevations in the Sierra Nevada mountains, the storm was expected to bring significant snowfall.

According to National Weather Service meteorologist Ariel Cohen, between 4 and 8 inches of rain had already fallen in some foothill areas by 9 a.m. PST. The Los Angeles City News Service reported numerous rockslides in mountainous regions, underscoring the instability of saturated terrain. Forecasts indicated that by the end of the week, more than a foot (30.48 centimetres) of rain could fall across some lower-elevation mountain areas.

In an unusual development, forecasters also issued a rare tornado warning for a small portion of east-central Los Angeles County after intense thunderstorm activity was detected over the community of Alhambra.

By Tamilla Hasanova