The last of falls leaves cling to the trees as snow gathers in Glenbrook Basin in Grass Valley, California. AP

Wintry weather bedeviled Thanksgiving weekend travellers across the United States on Saturday as a powerful and dangerous storm moved eastward, dumping heavy snow from parts of California to the northern Midwest and inundating other areas with rain.

Authorities found the bodies of two young children, including a 5-year-old boy, and a third child was missing in central Arizona after a vehicle was swept away while attempting to cross a runoff-swollen creek.

A storm-related death also was reported in South Dakota, where a small-engine plane carrying 12 people also crashed, killing 9 aboard and leaving three others injured. Peter Knudson of the National Transportation Safety Board said the Pilatus PC-12 crashed about 12:30pm on Saturday, shortly after taking off from Chamberlain, about 140 miles (225.3 kilometres) west of Sioux Falls. Knudson said weather would be among several factors reviewed by NTSB investigators, but no cause had yet been determined. He said inclement weather was making travel to the crash site difficult.

Meanwhile, the National Weather Service said the storm was expected to drop 6 to 12 inches (15-30 centimetres) of snow from the northern Plains states into Minnesota, Wisconsin and Upper Michigan.

Blizzard conditions early on Saturday were already buffeting the High Plains. The city of Duluth, Minnesota, issued a "no travel advisory” beginning at noon Saturday because of a major snow storm it termed "historic.”

Duluth officials asked the public to be patient as plows clear roadways and recommended that drivers stay off the roads to prevent accidents and let officers respond more quickly to emergencies.

Associated Press