(Adds detail about precipitation totals, deaths, closings, outages)
By Karen Brooks
AUSTIN, Texas, Dec 6 (Reuters) - A deadly winter storm some forecasters say is the worst to hit the United States in years slammed the nation's midsection Friday, snarling travel and knocking out power for hundreds of thousands of customers.
The line of ice, snow and freezing temperatures stretched from the Texas-Mexico border northeast to the Ohio Valley, with the most severe conditions near Dallas, then punching through Arkansas and western Kentucky, according to forecasters at AccuWeather.com.
Residents of large cities and small towns hunkered down against the storm. Many were without power as broad outages were reported through Texas, Arkansas and Louisiana, according to local utilities.
At the height of the storm, some 267,000 outages were reported in the Dallas-Fort Worth area alone, according to utility provider Oncor, but that number was down to about 208,000 by Friday afternoon.
More than 1,900 flights were canceled on Friday, according to online flight trackers.
First-time air traveler Madison Cunningham, 18, was stranded for more than 12 hours overnight in the Dallas-Forth Worth International Airport when ice prevented her flight home to Indianapolis.
"I'm never going to fly again," said Cunningham. "I'll take the train next time."
The travel troubles also delayed commerce, as the United Parcel Service, the nation's largest package delivery company, said deliveries have been disrupted in Arkansas, Missouri, New Mexico and the panhandle portion of Texas on Friday.
UPS staff meteorologists are tracking the storm closely, said UPS spokeswoman Susan Rosenberg, and the company may try to reroute some of its delivery network and use more rail.
At least three deaths had been attributed to the storm by Friday.
One of the casualties was the mayor of Granby, Missouri, whose vehicle veered off a snowy road and struck a tree on Thursday afternoon, officials said.
Ronald Arnall, 64, was killed on a state highway in southern Missouri, where up to eight inches of snow fell through early Friday and more was predicted. Arnall had been mayor since April in the town of 2,100.
"He cared about the city," said Granby City Clerk Paula Carsel.
In Arkansas, another man died when a tree fell onto his camper in Pope County, 80 miles west of Little Rock, during the storm late Thursday.
And in Texas, a man died when the BMW he was driving hit an 18-wheeler truck that was partially blocking a roadway near Dallas, police said. Police attributed the crash to icy conditions.
Sub-zero temperatures in the Dallas-Fort Worth metroplex expected through Sunday guaranteed that a layer of ice and sleet up to three inches on roads will go nowhere fast, according to the National Weather Service.
CITIES HALT ACTIVITIES
School closures, travel hassles and holiday event cancellations from Texas to Wisconsin piled up as the storm wore on.
Officials in Wausau, Wisconsin, canceled the city's holiday parade, scheduled for Friday, as the wind chill was expected to hit 25 degrees below zero.
Nashville's biggest night of holiday celebration was put on ice, literally, with the city's Christmas Parade canceled along with the city's Christmas tree lighting ceremony.
Instead of the usual fanfare at dusk, the city's mayor will simply flip the switch around 4:30 p.m. to illuminate the 30-foot Norway spruce with its 5,000 multi-colored LED lights.
A planned marathon in Dallas is a nonstarter, and an auction of Hollywood memorabilia, including '70s icon Farrah Fawcett's famous red swimsuit, planned for Friday, was postponed until next Thursday.
In Dallas, where forecasters are predicting up to a three-inch buildup of sleet, the city's Dallas Area Rapid Transit light rail was forced to shut down because of ice on the tracks.
The National Weather Service said it expected the harsh conditions to continue into the weekend, with temperatures about 30 degrees lower than average in some areas. (Additional reporting by Scott DiSavino, Nivedita Bhattacharjee in Chicago; Phil Wahba in Dallas; Kevin Murphy in Kansas City, Missouri; Brendan O'Brien in Madison, Wisconsin; Tim Ghianni in Nashville; Suzi Parker in Little Rock, Arkansas; Lisa Maria Garza and Marice Richter in Dallas; Editing by Colleen Jenkins, Lisa Von Ahn and Gunna Dickson)