This story was updated at 11 am ET on Sunday.

Sunday is shaping up to be a frustrating day for air travelers, as Winter Storm Blair spreads snow and freezing rain through the Central Plains and Midwest. The storm will move into the East South Central and Mid-Atlantic by Sunday evening and continue to impact the area through Monday.

The U.S. air travel system is feeling the storm’s impact. As of 11 a.m. Eastern Time on Sunday, there are 897 flight cancellations and 1,830 flight delays in and out of U.S. airports for the day, according to FlightAware, a free app that provides flight tracking data. Based on an historical trend analysis, many more cancellations will come as the day progresses.

FlightAware is showing triple-digit flight cancellations in Kansas City (MCI) and St. Louis Lambert (STL) airports.

ForbesWinter Storm Blair: Airlines Issue Travel Advisories Through MondayBy Suzanne Rowan Kelleher

Major U.S. airlines are issuing travel waivers allowing passengers flying in or out of impacted airports to rebook without paying the fare difference, but the number of airports covered varies widely by airline. For example, American Airlines’ travel advisory covers 46 airports while Delta Air Line’s advisory covers 20 airports.

For consumers looking to change travel plans or recoup travel expenses, much will depend upon the airline, itinerary and, in some cases, whether a travel insurance policy was purchased.

If you are flying through an airport covered by a travel advisory, it’s important to take advantage of airline waiver offers as soon as possible. Early birds have the best choices for rebooking flights for another day.

How to Predict and Manage a Flight Delay or Cancellation

Even if you’re not flying through an area affected by the storm, be prepared for disruptions. Statistically, your flight is more likely to get delayed the later in the day you fly. Flight disruptions tend to have a cascading effect because airlines reuse planes for multiple flights in the same day. So when a plane has a delay or cancellation on one flight, it will subsequently arrive late for the next one, and the next one, and so on.

A helpful tool on FlightAware can tell you if your plane is behind schedule, which can give you an early heads-up that a problem may be brewing. Enter your flight information, and then click the “Where is my plane now?” link just under the flight number. You’ll be able to see if the plane is ahead of schedule, on time or behind schedule and can take action accordingly.

Download the airline’s app and check your flight status before you go the airport. Most notifications are not at the last minute, so you may save yourself the drive to the airport. If you’re at the airport and get a notification that your flight is delayed or canceled, droves of people will race to the service counter. But often you can help yourself more quickly with the app. Also, keep your eyes peeled for self-serve kiosks with your airline’s brand.

Still, there are situations when you will need a human airline agent’s help. It will be first come, first served at the counter, so if have an early inkling that your flight will be delayed, don’t stray far from the departure gate. When it’s your turn, be polite. Rest assured, the agent is having a bad day, too.