A major winter storm that has dumped freezing rain and snow in the US southwest has killed at least 13 people in five states, US media reported.

The storm is expected to continue east over the next several days, just as tens of millions of travelers are expected to hit the road or take to the skies ahead of the US Thanksgiving holiday on Thursday.

Images from the storm-hit region showed thick layers of ice on sidewalks and icicles dripping off leaves.

The storm is forecast to bring substantial snow to the Appalachian mountains and New England, in the northeast, by Wednesday, which is one of the biggest US travel days of the year, according to meteorologists at Accuweather.com.

Further south, heavy rain could also hinder both road and air travel, they said.

The American Automobile Association predicts more than 43 million people will be traveling over the holiday weekend, in which many visit far-flung family to share the Thanksgiving meal.

Meanwhile, icy roads and flooding have already created hazardous conditions in Oklahoma, Texas, California, New Mexico and Arizona.

Four people died in separate crashes in Oklahoma, another four in two incidents in Texas, and a four-year-old child was killed when the car she was in rolled over in New Mexico, NBC news reported, citing state troopers and emergency personnel.

In California, where the storm hit first last week, one person was killed by downed power lines, another when a tree fell on her parked car, and a third in a traffic accident, NBC said.

And in Arizona, a person was swept away in storm-related flooding in the Santa Cruz river and his body was recovered Friday.