NEW YORK, Jan. 26 (Xinhua) -- At least 28 weather-related deaths were reported Monday as a massive winter storm dumped snow across dozens of U.S. states over the weekend, causing widespread power outages, flight cancellations and school closures.

The death toll included two people run over by snowplows in Massachusetts and Ohio, and fatal sledding accidents in Arkansas and Texas. In New York City, officials said eight people were found dead outdoors as temperatures plunged at night.

From Massachusetts in the northeast to Texas in the south, roads were frozen slick with ice and buried under often more than 30 cm of snow. In some southern states, residents faced winter conditions unseen for decades.

Nearly 700,000 customers from the mid-Atlantic to the South were without power as of 4 p.m. Eastern Time on Monday, according to poweroutage.com. Most of them were in the South, with Mississippi, Tennessee and Louisiana hit hardest, where freezing rain caused tree limbs and power lines to snap, inflicting crippling outages.

The storm snarled air traffic, with more than 12,500 U.S. flights canceled on Sunday, the most of any day since the onset of the COVID-19 pandemic in 2020.

As of Monday afternoon, more than 5,200 flights traveling into, from and within the United States were cancelled and over 6,600 were delayed, according to flight-tracking service FlightAware.

Ground delays were reported at major U.S. airports due to snow or ice, including Ronald Reagan Washington National Airport, Dallas Fort Worth International Airport and John F. Kennedy International Airport, according to the Federal Aviation Administration.

U.S. Transportation Secretary Sean Duffy said he hopes airports will be "back to normal" by Wednesday.

In New York City, all public schools were closed on Monday, and students learned from home.

While the storm system was expected to drift away from the East Coast into the Atlantic on Monday, a blast of Arctic air was rushing in behind it, prolonging sub-freezing temperatures for several more days, the National Weather Service said.

Connecticut Governor Ned Lamont announced that he is extending the state's severe cold weather protocol to Feb. 5 as the forecast predicted overnight single-digit temperatures over the next 10 days. Lamont said this was the longest such protocol in the state in over a decade. ■