Traffic snarls jammed Interstate 81 in stretches as long as 27 miles on the hectic Sunday after Thanksgiving, but most holiday travelers made their way safely through the Roanoke and New River valleys.

More than 35 wrecks were reported to the Virginia State Police between Montgomery and Rockbridge counties on Sunday, according to Sgt. Mike King, but no one was killed or seriously hurt in those crashes.

What officials did report were many backups resulting from fender-bender accidents that slowed down the hundreds of vehicles on the highways.

"This is one of the big days, and there was just a lot of bumper-to-bumper traffic, and a lot of impatient drivers out there," King said.

The Virginia Department of Transportation counted 575 vehicles per hour traveling north on I-81 past the Electric Road exit on Sunday evening, according to Heidi Coy, a spokeswoman. The average is 375 per hour on any other Sunday of the year, Coy said.

The most densely congested area was I-81 North just south of Christiansburg. VDOT reported traffic backed up as much as 27 miles from as early as 1 p.m. until about 7 p.m.

King said that only minor wrecks had been reported in that area, but that with such a high volume of traffic a small incident could easily start what he called "domino effect" backups.

Traffic also backed up more than four miles on I-81 between Electric and Plantation roads in Roanoke County and near Buchanan in Botetourt County.

About 895,000 Virginians were estimated to be traveling 50 miles or more on the road to celebrate Thanksgiving, and slightly more than 1 million to be traveling by some means, according to AAA estimates.

On Sunday afternoon, the hallways were clear at Roanoke Regional Airport. Persistent rain in the Roanoke Valley was not enough to cause flight delays, but two departing flights were cancelled because of congestion in other cities, said Sherry Wallace, an airport spokeswoman.