BUFFALO, N.Y. >> Snow and cold records fell from the Plains to the Great Lakes and beyond as an arctic airmass that started in Siberia spilled over a big chunk of the eastern half of the U.S., including the normally mild South, today.

The mid-autumn taste of winter brought record single-digit temperatures to Chicago and environs; set snowfall records in Buffalo and Detroit; dusted cars with snow in Memphis, Tennessee; and froze lakes in Minnesota weeks earlier than usual.

“This is an air mass that’s more typical for the middle of January than mid-November,” National Weather Service meteorologist Kevin Birk said in Chicago, where this morning’s low of 7 degrees broke the previous record of 8 degrees, set in 1986. “It is pretty much about the coldest we can be this time of year (and) it could break records all over the region.”

The roughly 10 inches of snow in Buffalo and Detroit by this morning were record depths for the time of year, weather service records show. Areas of Vermont and Maine prepared for similar totals as a wintry mix also closed or delayed hundreds of schools in northern New England.

In St. Louis, the mercury dipped to 11 degrees today, breaking a record for the date that had stood since 1911.

Warming shelters in Memphis offered relief from temperatures in the low 20s.

Schools and businesses as far south as the Gulf Coast states opened late or closed today because of the unusual cold.

About 20 school systems delayed opening across north Alabama under the threat of wintry precipitation, including all the public schools around Huntsville.

Even more opened late or closed in Tennessee, and a handful of businesses and schools opened late in Georgia.

Forecasters said daytime temperatures would remain in the 30s across a wide area of the South. Freeze warnings reached from eastern Texas to coastal South Carolina, with overnight lows predicted in the 20s.

The dip to 8 degrees in Indianapolis gave the city its earliest recorded fall temperature in the single digits. The closest similar reading was 11 degrees (minus 11 Celsius) recorded on Nov. 3, 1951.

Farther north, heavy lake-effect snow piled more than 10 inches high near Goshen.

Seven passengers on a New York City-bound bus escaped serious injury when it turned on its side on a snow-slicked highway south of Syracuse early today in one of many traffic accidents. A section of Interstate 90 in Pennsylvania was back open today after being closed overnight because of jackknifed tractor-trailers.

The Eaton County Sheriff’s Office in Michigan said two women, ages 81 and 64, and a 57-year-old man were killed Monday in a two-vehicle crash caused by poor road conditions. And in Kansas, the Highway Patrol said an 8-year-old girl died in a three-vehicle wreck.

Officials in central Wyoming searched for a 16-year-old boy with autism who disappeared Sunday wearing only his pajamas.

In Chicago, a plane landing Monday at O’Hare International Airport slid across the runway. No one was injured. More than 1,000 flights at O’Hare and Midway International Airport were canceled after more than 3 inches of snow fell.

In some areas, the mercury fell quickly. Temperatures in Denver climbed past 70 degrees over the weekend only to fall to 14 degrees early Monday.