Airlines are canceling hundreds of flights around the country due to a kind of storm that happens "once every 20 years." By Sunday, the storm may be "as strong as a Category 1 hurricane," according to the National Weather Service.

Here are six tips if your travels are affected:

1. If you're at the airport and your flight is canceled, get into line to re-book yourself on the next flight out. But be sure to also whip out your cell phone and call the airline on its toll-free number while you wait. You may get through to customer service faster on your phone. For a wallet card of airline phone numbers, click here. (You may need to install free Adobe Reader software on your computer to open this card.) If you decide to rebook your flight, be sure to find out the rules and regulations. Some airlines require that you make new reservations immediately, while others will allow you to rebook within a year.

2. There's no blanket travel cancellation policy. Policies and contracts of carriage vary from airlines to airline, hotel to hotel, and change all the time. It's best to check with your airline and hotel directly to find out what their current policies are before you go.

3. For traveling to any international destination, expect to spend at least $200 to change your ticket, but contact the airline before your originally scheduled departure date. Changing tickets after the flight has left is often much more complicated.

4. Keep in mind that some airlines do not refund tickets purchased through a third-party discounter, or on the Internet through sites like Orbitz. Call the agency or packager you booked through first to see what's possible.

5. Most hotels give full, or at least partial, refunds if a storm hits (or is expected to hit) during your stay.

6. While it's more complicated with airlines, many carriers do make attempts to accommodate passengers. In the past, many airlines have allowed passengers to change their tickets within a specific time frame in the case of a terrorism attack with "Peace of Mind" policies that allow passengers to rebook tickets free of charge, or receive credit for a future trip. It's good business, and once one major airline allows changes, many follow suit.