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

The rain that is expected to hit the scorched Los Angeles landscape this weekend may bring relief to the fire fights, but it could also bring flash floods and mudslides. Although forecasts show that the risk is relatively low, local officials are taking the warnings seriously.

The first significant storm of the season 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 on Monday.