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(CNN) -- A deadly winter storm that began in Southern California and stretches to Texas threatens to wreck Thanksgiving week travel plans all the way to the Atlantic.
At least six people have lost their lives in traffic crashes blamed on the storm system since late last week.
An arctic air mass is expected to keep temperatures 15 to 20 degrees below normal along the East Coast through Thursday. Even if the system fails to deliver heavy snow, it could cause air travel disruptions with high winds, forecasters say.
Airlines flying in and out of Dallas/Fort Worth International Airport "pre-canceled about 300 departures to reduce the number of stranded travelers" Sunday in "anticipation of winter precipitation," the airport's official Twitter account said. Ten percent of flights at Oklahoma City's Will Rogers World Airport were also canceled due to the weather Sunday.
Three travelers died in a multi-vehicle crash on icy Interstate 40 in northwest Texas late Friday, Texas State Trooper Chris Ray said.
The dead included a person who got out of his vehicle to render aid and was struck, Ray said. Anther 11 people were injured in the crash, some critically.
At least 20 people were taken to local hospitals from collisions within three miles of the fatal pileup, according to Oldham County, Texas, Sheriff David Medlin.
"We have about 4 inches of snow on the ground," Medlin told CNN on Sunday. "Road conditions are still dangerous, and people should drive cautiously and avoid roads unless absolutely needed."
A 4-year-old girl was killed Friday when a car carrying her slid off icy U.S. Highway 70 in New Mexico, said the state Department of Public Safety. The child was not properly restrained, the department said.
Also in New Mexico, a woman in her 50s died Saturday when the pickup truck that she was riding in rear-ended a semi-truck during heavy traffic near Gallup, New Mexico State Police said.
In Yuba County, California, a 52-year-old passenger in a car died when a tree fell on top of the vehicle Thursday, the county sheriff's office said.
Ice is blamed for causing Willie Nelson's band bus to spin out of control and crash into a bridge pillar on Interstate 30 near Sulphur Springs, Texas, early Saturday. Three of the five members of Nelson's band were hurt, according to police and the band. Nelson was not on board.
Flood threat in Arizona
Lingering rain prolonged the flood threat in Arizona, the National Weather Service said. Friday's 1.6 inches of rain in Phoenix made it the second wettest November day ever recorded in the desert city. Lighter amounts fell Saturday, but drainage areas already were full.
In New Mexico and West Texas, snow and ice covered Interstate 10. The highway was open through Texas, but officials urged caution, especially on bridges.
New Mexico could see up to 8 inches of snow accumulating through Monday.
Storm will reach Carolinas by Monday
On Sunday, the forecast for northern Texas and parts of Oklahoma called for rain and sleet, and some spots were expected to get up to 4 inches of snow. Rain and sleet will extend through Dallas and into northern Louisiana.
"Tomorrow is going to be the big event. After midnight, it's going to be so close to freezing, that's when we're anticipating it to be bad," Sgt. Lonny Haschel with the Texas Department of Public Safety said Sunday.
Rain is expected to stretch from Texas to Georgia on Monday and to the Carolinas on Monday night, with sleet and snow in northern parts of that swath. The heaviest rain is expected across parts of Mississippi, Alabama, Georgia, Florida and South Carolina.
By Tuesday, the rain will reach the mid-Atlantic states and parts of the Northeast. Freezing rain could develop in the southern and central Appalachians.
Travel delays next week in Northeast
Rain, wind and possibly snow will cause travel delays beginning as early as Tuesday in the East, said CNN meteorologist Melissa Le Fevre.
"We are going to see delays," Le Fevre said. "We're just waiting to see if the impacts are going to be severe or just annoying."
The deciding factor will be whether a low-pressure system moving north out of the Gulf of Mexico travels inland or close to the East Coast, she said.
According to AAA projections, 43.4 million Americans will travel 50 miles or more from home during the Thanksgiving holiday weekend this year.
CNN's Karen Maginnis, Judson Jones, Joe Sutton, Nick Valencia and Janet DiGiacomo contributed to this report.