There have been multiple casualties in a huge landslide that buried cars and houses in mud and debris in Rural Washington State in USA.Eighteen people were still missing on Sunday after rain-soaked embankments along State Route 530 near Oso, about 90km northeast of Seattle, gave way a day earlier and washed out at least six homes.The slide in the foothills of the Cascade Mountains along the Stillaguamish River piled mud, rock and debris up to 5 meters deep in some places.The slide wiped through what neighbours described as a former fishing village of small homes, some nearly 100 years old.