At least 13 people are dead amid “waist-deep” mudslides in Southern California, where heavy rains triggered flooding, say officials. Some 163 people have been taken to hospital. Twenty had “storm-related injuries” and four were critically hurt. A group of up to 300 people are reportedly trapped in Romero Canyon, east of Santa Barbara. Police said the scene “looked like a World War One battlefield”. The flooding and mudslides, affecting areas scorched by wildfires last month, have shut down more than 30 miles (48km) of the main coastal road. Emergency services said a number of people were unaccounted for and they expected the number of deaths to rise. Thousands fled the deluge and more than 50 rescues have been performed. The hardest-hit homes were those that were not in the evacuation zone, officials say. Heavy rain run-off caused a mudflow in the community of Montecito, where some homes were knocked off their foundations, said Santa Barbara County Fire Department spokesman Mike Eliason. Boulders the size of small cars were rolling down hillsides and blocking roads, reports BBC News Los Angeles correspondent James Cook. Among those taken to safety was a 14-year-old girl who had been trapped for hours in the ruins of her home. The fire department published a picture of the girl encased in mud as she was led to safety.