The strongest winter storm so far this season is wreaking havoc on air travel across large swaths of the country.

Snow, ice and frigid air are battering much of the Midwest, disrupting thousands of flights, and conditions could get worse as the system moves toward the East Coast.

As of 1 p.m. ET on Sunday, US Airways had canceled more than 1,100 flights, according to FlightAware. Another 3,300 people were delayed.

Missouri’s Kansas City International Airport (MCI) has experienced the worst flight disruptions so far, with nearly 90% of scheduled flights canceled due to blizzard conditions on Sunday.

The widespread cancellations come a day after the airport at one point had to close its runways due to rapid ice accumulation, briefly threatening plans for a Kansas City Chiefs game in Denver on Sunday.

Forecasters have been warning for days of severe disruptions to travel as last week’s winter storm developed, with the National Weather Service warning of the potential for significant amounts of snow from the Midwest to the Washington, D.C., metropolitan area.

AccuWeather meteorologist Brandon Buckingham said Friday: “Snow accumulations are expected to approach or exceed half a foot, bringing traffic to a standstill in places like Kansas City, St. Louis, Indianapolis and Cincinnati.” States across the mid-Atlantic will be preparing for “weekly “Travel between Sunday night and Monday night poses a significant risk.”

As early as Friday, Ronald Reagan Washington National Airport (DCA) said its airport snow removal team would monitor the situation and plan to deploy snow removal equipment as needed.

Philadelphia International Airport (PHL) similarly warned of possible hazardous conditions Monday morning.

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Most major U.S. airlines have issued travel alerts to give passengers more flexibility to change their itineraries in the event of severe weather. This includes waiving change fees even for travelers traveling on the most restrictive fare types.

Southwest Airlines was one of the hardest-hit airlines on Sunday, with more than 300 flight cancellations, the most of any U.S. airline, accounting for about 7% of its flight schedule. The Dallas-based airline has sizable operations in hard-hit Kansas City and St. Louis, not to mention Washington, D.C., which is expected to bear the brunt of the storm in the coming hours.

American Airlines has canceled more than 100 flights so far Sunday due to ground groundings driven by winter storms and high midday winds at its base at DFW, according to the Federal Aviation Administration. flights.

If you’re traveling in the next few days, here’s what you need to know:

Pay attention to travel advisories

Check your airline’s website. Your flight may be covered by one of the many travel advisories issued by major U.S. airlines.

This makes it easier to change your itinerary for free directly from the airline’s app – even if you’re flying on a typically restricted ticket like basic economy.

American Airlines, for example, issued an advisory covering nearly three dozen airports across much of the country, including its Philadelphia and DCA hubs.

United has done the same at nearly a dozen airports, including its Washington Dulles International Airport (IAD) hub. Southwest’s travel alert covers several cities where it has major operations, including Kansas City, St. Louis, Nashville and Baltimore/Washington International Thurgood Marshall Airport (BWI).

Here are links to travel advice from the four major U.S. airlines:

It is worth noting that many airlines also issued travel warnings last week following the terrorist attack in New Orleans on January 1.

See a good rebooking option? don’t delay

If you’re battling a flight delay and see a great rebooking option pop up in your airline’s app, don’t waste a second: lock it in!

Thousands of scheduled flights were canceled due to bad weather, with large numbers of passengers simultaneously competing for space on flights that departed on time. These slots will be filled quickly.

Learn more: Flight canceled or delayed? This is what to do next

Stay home? You may be eligible for a refund

If your flight is canceled or severely delayed and you choose to stay home instead of flying and riding out the winter storm, you should be eligible for a refund.

The U.S. Department of Transportation stipulates that when a flight is canceled or severely delayed, airlines should refund passengers the portion of the ticket that did not take off, but only if the passenger chooses not to travel rather than accept a rebooking.

Easily cancel your award booking and get your miles back

In the meantime, if nature makes you want to stay home and forego that trip you booked with frequent flyer miles, you’re in luck.

Generally speaking, most U.S. airlines will let you cancel your award booking and get all your miles back for free. You’ll also usually get a refund of any relevant taxes.

Take Advantage of Airline Lounge Customer Service

Stranded at the airport? If you’re a member of an airline lounge, don’t forget: There are usually customer service agents there to help you plan your itinerary — and the wait times are usually shorter than what you’d find in an airport lobby, where the crowds line up.

But remember, this applies to the airline-branded lounges of the airline you’re flying with, not the credit card-branded lounges.

Read more: 5 ways to make sure you have lounge access before your next flight

Get flight delay compensation

Airlines made broad commitments to the Department of Transportation, providing meals, hotel accommodations and other guarantees in the event of flight cancellations and severe delays. However, these generally apply to “controllable” outages (such as maintenance or staffing issues) – and often they do no Applies when bad weather affects travel.

That’s where a travel credit card that offers travel insurance coverage can come in handy, helping you recoup unexpected expenses when you’re stuck because of a flight failure. There’s a catch: In most cases, you usually need to book a trip with the card in order to successfully claim.

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