A massive storm that formed in the Pacific Ocean reached drought-stricken California Friday, causing some streams and rivers to rapidly fill with racing muddy water and raising the threat of mudslides, according to dpa. More rain fell on Friday in Los Angeles than in all of last year, news reports said. The storm dumped more than 10 centimetres of rain in parts of the greater Los Angeles area within a 10-hour time span, according to the city's water department precipitation map. The last time the city experienced significant rainfall was in March 2012 when just over 2 centimetres fell, according to Los Angeles Times. Although the rain is welcome, it is bringing a slew of dangers to the area. Officials warned that the deluge could cause mudslides by loosening the topsoil on the parched hills that just a few months ago were plagued by wildfires. A mandatory evacuation order is in place for parts of the cities of Glendora, Azusa and Monrovia, where the more than 1,000 homes were threatened by mudslides. Mud was flowing down the hillsides, scorched by fire a month ago, turning some roads of Azusa and Glendora into raging rivers, according to multiple media reports. Some backyards already were inundated by debris and mud. The fire destroyed more than 6,9 square kilometers of brush in the area and now there is no vegetation left to hold the mud back. Monrovia issued the mandatory evacuation order for burn areas from a fire in that area that scorched about 0.7 square kilometres in the San Gabriel Mountain foothills in April. A flash flood watch is in effect until Saturday and a high surf advisory, a coastal flood advisory and a winter storm warning are in effect until Sunday, according to the National Weather Service. The winter storm knocked out power for about 32,000 people in Los Angeles. The power company Edison of Southern California reported 18,000 customers without power and the Los Angeles Department of Water and Power said about 14,000 of its customers were left in the dark. Officials are pleading with residents to leave the area threatened by mudslides. "As long as the mud is flowing the fire department personnel cannot get to you," said Los Angles County Assistant Fire Chief Steve Martin said at a news conference Friday. Despite the mandatory evacuation some homeowners decided to stay and try to safe their homes, according to local media reports. "It's a little scary, but we want to stay. It's hard to move with three dogs," told Yvonne Bobadilla of Glendora the local ABC television affiliate. The Los Angeles Department of Public works reported about 13-road closure Friday afternoon mostly due to flooding, rock-slides and potential mudslides. The wet weather is expected to continue through Friday night. The winter storm will bring snow to higher elevations, which is good news for skiers and businesses in local ski resorts. Several centimetres of snow are expected in the ski resorts in Big Bear, according to meteorologists. California has been suffering its worst drought in over 100 years, but experts said the storm would not deliver enough rain to reverse it.