Widespread flight cancellations continued Tuesday as a winter storm pummeled the eastern U.S., causing headaches for thousands of travelers. 

As of 4:20 p.m. Eastern Time, airlines had scratched more than 2,200 scheduled U.S. flights, while roughly 6,800 flights were delayed, according to tracking service FlightAware. Thousands more trips were canceled or delayed over the weekend as harsh winter weather, including freezing temperatures, snow and strong winds, enveloped states in the Midwest, Northeast and South.

Among the hardest hit airlines is Southwest Airlines, which on Tuesday scrapped more than 400 flights, or 11% of its daily schedule, while another 909 were delayed. Cancellations were also high at Alaska Airlines and United Airlines as they continued to deal with concerns over the safety of some Boeing 737 Max 9 jets following a mid-air incident last week in which a “door plug” fell off an Alaska Airlines plane.

Unlike in 2022, when airline mismanagement and staffing shortages affected holiday travel, bad weather is the main culprit behind the current woes.

“The winter weather is the primary catalyst, but the big challenge is that this weather has been so intense and extensive,” airline Henry Harteveldt, president of Atmosphere Research Group, told CBS MoneyWatch.

The schedule disruptions are severe enough that staffing is starting to run thin across airlines, while de-icing fluid was also in short supply Tuesday, Harteveldt added. “When you’ve got delays at major airports, everything just gets spread out across the entire aviation network and there’s a waterfall effect,” he said. 

Travel industry expert Scott Keyes said the true test of airlines’ readiness will be in how they rebound once the weather eases in the coming days.

“For now the cancellations and delays are understandable and forgivable. In the next days, when the weather improves, all eyes will be on airlines to see if they are able to bounce back quickly or if they suffer from more cancellations that are the result of a lack of preparation,” he said.

By contrast, airlines will have to consider future investments to preserve their operational efficiency in the face of worsening winter storms. 

“Once airlines and airpots get through this latest bout of bad weather, they need to really sit down and think about how they prepare for a future where bad winter weather storms may be more frequent, last longer and potentially have even greater temperature and weather extremes than we have seen,” Harteveldt said. 

In airlines’ favor on the staffing front is the fact that this weather event is occurring in the middle, not the end, of the month. Federal law caps the total number of monthly hours that crews can work, including flight attendants and pilots. If it were closer to the end of the calendar month, crews could be at greater risk of maxing out their hours. For example, time spent waiting for aircraft to be de-iced before takeoff is applied toward employees’ schedule caps.

“I am concerned if we see bad weather happen again that this could have a cascading effect and we could see worse problems later in the month,” Harteveldt said. 

When bad weathers occurs, travelers should download their carrier’s app and pay attention to airline updates, he noted. If checking bags is a must, keeping essentials in a carry-on is advisable in case you end up stuck at the airport.