In Southern California, the death toll from a series of mudslides has risen to 17, as rescue workers scrambled to save residents whose homes were buried under an avalanche of mud, boulders and downed trees. The deadly mudslides followed an unprecedented winter fire season, which saw the state’s worst wildfire on record rage for days north of Los Angeles. The fires stripped vast areas of vegetation and opened up hillsides to collapse when heavy rains returned to California this week. Climate scientists say greenhouse gas emissions contributed to the wildfires and extreme weather.