Exceptionally dry weather has targeted Southern California so far this winter, creating ideal conditions for wildfires.

So far, many clues to the origins of the deadly Eaton fire, which started in the area just after 6 p.m. that evening and went on to kill 17 people, have pointed to the brushy hillside where a tangle of electrical lines stretch up Eaton Canyon.

Southern California’s first significant storm of the season brought weekend downpours that aided firefighters but caused ash, mud and debris to flow across streets in wildfire-burned areas.

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 the season for the region that had not seen rainfall for eight months.