Omicron, weather cause travel chaos as thousands of flights canceled

Airlines blamed the spread of the  omicron  variant for travel disruptions that saw some 10,000 flights canceled globally over the holiday weekend and into Monday, as storms in the western United States compounded the chaos.

Whiteout conditions in northwestern Nevada caused a 20-vehicle pileup on Sunday, officials said.

Meanwhile, from Dec. 24 to Dec. 26, around 8,000 flights were canceled, according to  data published by online flight tracking platform FlightAware . A  number of airlines, including Delta, United, JetBlue and Alaska, blamed COVID-19 infections , including those connected to the highly transmissible omicron variant, for the difficulties.

In a statement on Sunday, Delta said "winter weather in portions of the U.S. and the omicron variant" were both taking a toll on the airline's holiday weekend flight schedule. 

Of 4,155 total mainline and connection flights scheduled Sunday, it said it had canceled 161, with around 40 more cancelations forecasted for the day. 

JetBlue said it had about 110 cancellations on Sunday, with the number expected to potentially grow depending on crew availability.

"We have seen an increasing number of sick calls from omicron," the airline said, adding it had entered the holiday season with the highest staffing levels since the pandemic began.

"Despite our best efforts, we've had to cancel a number of flights, and additional flight cancellations and other delays remain a possibility."

By early Monday morning, another nearly 2,000 flights around the world were  canceled for the day following the Christmas weekend , with at least 629 of those flights expected to have flown within, into or out of the United States, according to FlightAware.

The cancellations come as many around the world will likely be trying to return home after visiting loved ones over Christmas weekend.

They also come after nearly 190,000 new COVID cases were reported in the U.S. on Dec. 26 alone, according to a  tracker maintained by The New York Times , which noted that holiday interruptions to testing and data reporting could affect the count.

The Centers for Disease Control and Prevention did not update their  COVID tracker  over the weekend, but is expected to resume posting data later on Monday.

As omicron wreaks havoc on Christmas travel plans across the country and around the world, winter storms in the western U.S. have also caused chaos.

More than 20 vehicles were involved in a crash in northwestern Nevada, with drivers reporting whiteout conditions, the sheriff's office said.

In a separate statement, the Truckee Meadows Fire & Rescue said  at least three people were taken to the hospital  following the pileup.

"Conditions are extreme in the Washoe Valley with 50 mph winds and white out conditions," it said in a Twitter post.

The National Weather Service's office in Reno warned in a tweet that it was the "type of day to just stay home if you can."

Later, it shared video of the dangerous driving conditions, saying its officers were "having a hard time finding the road."

By Monday, a duo of storms was expected to see significant snowfall continue for portions of the West Coast mountain ranges and the Intermountain West,  according to the National Weather Service.

As one storm is expected to weaken by Monday night, the next system already causing heavy mountain snow was expected to make its way across the Intermountain West overnight and into Tuesday morning, with the Sierra Nevadas expected to reach totals of up to 3 feet of snow at the highest elevations.

Storms were also expected to bring record cold to parts of the West Coast, with snowfall also expected in the Upper Midwest and an "icy wintry mix" set to hit the central Great Lakes and northern Mid-Atlantic, the weather service said.

"Travel delays due to icy conditions are possible in these regions, both on the ground and in the air," the National Weather Service warned.

Record cold temperatures could also be possible along the West Coast on Monday, the weather service said.

As the West faces snow and icy conditions, the South may see record warm temperatures over the coming days, as the region continues to see a holiday heat wave.

This article was originally published on NBCNews.com .

This article was originally published on TODAY.com