A massive winter snowstorm making its way across the Midwest and into the US mid-Atlantic region dumped more than a foot of snow in parts of Missouri and contributed to at least five deaths, authorities said on Saturday.

The storm moved into Kansas and Nebraska from the Rockies on Friday, then east into Missouri, Iowa, Illinois and Indiana, covering roads and making driving dangerous.

Part of Interstate 44 near St Louis was blocked for several hours and at one point the Missouri state highway patrol warned of traffic delays as long as eight hours.

The storm was expected to spread east with between 3in and 6in of snow expected in the Washington area, including parts of northern and central Maryland, by Sunday. Forecasters said heavier snow and higher amounts could fall in mountain areas north of Interstate 64, such as Charlottesville and Staunton, Virginia.

Missouri had the worst of the storm by Saturday, with the National Weather Service reporting more than a foot of snow in some places around St Louis and Jefferson City, and more than 18in in Columbia.

At least five people were killed in crashes on slick roadways in Kansas and Missouri. They included a woman and her 14-year-old stepdaughter whose car slid into the path of a semitrailer in Clinton, about 80 miles south-east of Kansas City, on Friday, the Missouri highway patrol said. Another woman died when her car slid on US24 in northern Missouri and was hit by an SUV.

In Kansas, a 62-year-old man died after his pickup truck skidded on the Kansas Turnpike and hit a concrete barrier, according to the patrol. Another crash involving two semitrailers in snowy conditions killed a 41-year-old driver from Mexico, the patrol said.

“We’re anticipating still more snow through today, so we’re asking motorists to stay home until the roads are cleared,” said Missouri highway patrol Sgt Collin Stosberg. “If you do have to get out on the road, we’re asking you to do three things: have your cellphone fully charged, wear your seat belt and slow your speed for the conditions.”

Missouri troopers responded to more than 3,000 calls for help through early Saturday afternoon, including more than 700 crashes and 1,300 stranded vehicles. Illinois state police said troopers along the Mississippi river across from St Louis had responded to more than 100 crashes.

At Lambert International Airport in St Louis, most flights were canceled or delayed. In central Missouri, officials said about 12,000 households and businesses were without power in Columbia and the surrounding area at one point.