(CNN) -- Check with your airline before you head to Hartsfield-Jackson Atlanta International Airport today.
Airlines had canceled more than 3,200 flights within, into or out of the United States shortly before 10 p.m. ET, according to FlightAware.com. And many of those canceled flights involve the world's busiest -- but not the snowiest -- airport.
The last time the Atlanta airport used its four snow plows to actually plow snow was the great snow storm of January 2011, said airport spokesman Reese McCranie. The airport also has six snow brooms, four de-icers, seven spreaders, 100,000 gallons of de-icing fluids, 50,000 pounds of de-icing solid material and 50,000 pounds of a salt/sand mix to clear roadways.
As this latest winter storm crosses the country, flights at the Atlanta, Houston and Chicago airports have been the hardest hit by cancellations.
Hartsfield-Jackson Atlanta is reporting 930 flights canceled, Houston's Bush Intercontinental Airport is reporting 696 flights canceled and Chicago's O'Hare International Airport is reporting 548 flights canceled. The numbers of arriving and departing flights canceled are expected to increase.
"Some planes are getting de-iced ... and we're also putting preventative de-icing material on the (five) runways," said Houston's Bush Intercontinental Airport spokeswoman Darian Ward.
The airport has shut down an above-ground train that ferries passengers between terminals. Instead, passengers are being asked to ride buses. Airport operations may return to normal soon if it warms up today, Ward said.
Chicago's O'Hare has been hit by airlines that are proactively canceling flights. O'Hare -- an airport with a bit of experience with snow removal -- reports only 15-minute delays for arrivals and departures. "Our snow operations teams are out and doing their jobs," said Karen Pride, Chicago's Department of Aviation spokeswoman.
Cleveland weather isn't slowing down most flights, either. Thirty percent of Cleveland Hopkins International Airport's Tuesday flights -- mostly smaller aircraft -- have been canceled. "This is due to airline pull downs (reductions because of bad weather in other locations) and not because of weather," said airport spokeswoman Jacqueline Mayo.
Call your airline to change your flight
Many airlines with flights departing and arriving at hardest-hit cities are offering flexible change policies for delayed customers. Check your airline website for more information.
Delta Air Lines canceled more than 1,800 Delta and Delta Connection flights Tuesday, the vast majority at its Atlanta hub, said Delta spokesman Morgan Durrant.
The nasty weather forced American Airlines to cancel about 350 flights Tuesday, mostly regional flights across the Gulf Coast, Mid-Atlantic and Midwest, an airline spokesman said.
While declining to give specific numbers, United Airlines is "reducing operations at Houston Intercontinental Airport and other airports in the mid-South and Southeast regions today due to severe weather," said spokesman Charles Hobart, Tuesday. Citing near-record lows in the Midwest, United is also reducing operations Tuesday at their Chicago and Cleveland hubs and other Midwest airports.
Make sure to confirm flights Wednesday
Depending on how-hard hit they are, Houston and Atlanta airports may still be recovering from storm conditions on Wednesday, said David Baker, FlightAware's chief executive officer. The Chicago and Cleveland airports could also face delays, depending on weather conditions in those Midwest cities.
And what about your Amazon delivery?
Severe winter may also affect the delivery of your packages. Remember how winter storms slowed pre-Christmas deliveries? FedEx, which is posting service alerts on its website, has already warned customers that hazardous conditions in Louisiana, Mississippi and Texas may cause delays in Illinois, Indiana, Kentucky and 12 other states.
UPS is reporting "severe weather impacts" in some of its delivery areas, according to company spokeswoman Susan Rosenberg. Check UPS.com to see which zip codes are affected. "We make every effort to maintain service as long as safety permits," she wrote, via email. "If deliveries are interrupted, we will resume service as soon as it is safe to do so."