The first significant storm of the season has brought snow and downpours to Southern California that doused wildfires and caused some ash and mud to flow across streets in the Los Angeles area.

Snow shut down a key interstate north of Los Angeles for hours on Monday while weekend downpours doused wildfires across Southern California in the first significant storm of

Much-needed rain has begun to fall over Southern California, bringing relief to the drought-stricken region but also the threat of toxic runoff.

More rain fell Monday on parts of Southern California after causing mudflows over the weekend, helping firefighters but boosting the risk of toxic ash runoff in areas scorched by Los Angeles-area wildfires.

Less than an inch of rain fell in most areas, but it was enough to loosen Los Angeles hillsides burned bare by the recent blaze near the Pacific Palisades.

AccuWeather's California Expert Ken Clark talks about the much-needed rain hitting California. Investors made a quick exit from a host of technology stocks from Tokyo to New York on Monday as the emergence of a low-cost Chinese artificial intelligence model challenged the dominance of current AI leaders such as Nvidia .