Southwest workers stand near baggage cars next to a Southwest jet.

During this past week of delayed and canceled flights, lost luggage, and being stranded far away from friends and family, that was nothing compared to what Southwest Airline ground crew workers experienced, according to a union letter.

Southwest Airlines ground crew workers are represented by the Transport Workers Union of America. TWU Local 555 President Randy Barnes said in a release that a lot of their members were working 16- to 18-hour shifts. He said that some people were getting sick and that some people were getting frostbite.

Barnes said that people need to be able to cycle in and out of the cold. The ground crews of the airline need to be protected.

A leaked email shows that Southwest declared a state of operational emergency in Denver. The memo shows that ramp workers were required to work overtime, and if they were sick, they were also required to give a doctor's note. Business Insider said the document was confirmed by the company.

The average temperature in Colorado was -15 F on December 22. It's all before the wind chill, which can be the deciding factor when it comes to frostbite.

Barnes criticized the Dallas, Texas-based airline for scheduling so many flights despite the weather conditions. Southwest needs to space flights out more during extreme weather.

We didn't hear back from the union after we contacted them to find out what the severity of sickness was for Southwest ground crews. Southwest wouldn't comment on its policies for ground crew during bad weather. Southwest can contractually implement emergency procedures for ramp workers, according to Insider.

It can take a short time to develop frostbite. A chart on the National Weather Service's page shows the temperature and wind speed needed to cause frostbite in 30 minutes, 10 minutes, or just 5 minutes. A person in a wind chill of -20F would take 30 minutes to develop frostbite. It's important to see a doctor to gauge the severity and get accurate treatment for milder forms of frostbite.

The winter storm has caused Southwest to cancel thousands of flights. The airline canceled thousands of flights for Tuesday and Wednesday. Since December 22, Southwest has stopped flying. Southwest's scheduling software was blamed for much of the travel chaos. There wasn't enough staff for the airline.

The company pointed out a video with Southwest CEO Bob Jordan. Jordan made a statement.

“The operation of the airline counts on all the pieces, especially aircraft and crews remaining in motion to where they’re planned to go. With our large fleet of airplanes and flight crews out of position in dozens of locations. And after days of trying to operate as much of our full schedule across the busy holiday weekend, we reached a decision point to significantly reduce our flying to catch up.”

Southwest was originally intended to be a point-to-point airline that avoided the excesses of other major plane-based businesses. Southwest has become more similar to its pricier competitors since the departure of its CEO. When the company canceled thousands of flights and lost hundreds of pieces of luggage in the winter of 2014, it was just one example of how it lags behind. The company canceled more than 2,000 flights last year due to bad weather.

The federal government is breathing down Southwest because of this failure to operate. While other airlines have improved their services, Southwest Airlines has moved in the other direction, according to Pete Buttigieg. Southwest has crossed the line from an uncontrollable weather situation to something that is the airline's direct responsibility, according to him.

They need to care for their passengers and employees. According to the New York Times, the Senate Commerce Committee will investigate Southwest.

The east coast of the United States was hit by a winter storm on Friday that buried Buffalo, New York under several feet of snow. As of Tuesday, federal officials said the storm has claimed at least 63 lives, but that number will likely rise in the coming days.