[Rick Seaney is the CEO and cofounder of FareCompare, and a featured columnist for Investopedia. The views expressed by columnists are those of the author and do not necessarily reflect the views of Investopedia.]

Most airlines really hit you hard if you try to alter a ticket in any way, shape or form – including something as simple as moving a date or time. Try it and American, Delta and United will sock you with a $200 change fee (more for international flights) while you’ll pay varying prices to other carriers. Southwest is the lone domestic hold-out that allows changes for free.

When Change Fees Get Waived

But wait: There is one exception, one that many travelers have experienced over the past several days: bad weather. It’s been slamming lots of regions and airlines to their credit have been proactive in allowing customers to change their plans ahead of the storms – with no penalty. Airlines call this disappearing change fee a weather travel waiver, but I just call it common sense.

Why Airlines Waive Fees for Weather

For the airlines, weather waivers save a lot of headaches. It’s a whole lot easier to work on Plan B for getting a plane in or out of a bad weather zone when you aren’t also dealing with hundreds of passengers surrounding an airport gate agent while pleading, “What do we do now?” What you do is simple: Check with your airline the moment you hear about any well-publicized storm that might disrupt flights to see if your airline is waiving change fees. If they are, jump in and take advantage. 

Change-fee weather waivers may also help prevent PR messes: Anyone remember JetBlue’s notorious 2007 Valentine’s Day debacle when storms stuck passenger-filled planes on the tarmac – in one case for more than 10 hours? Eventually, the Department of Transportation began fining airlines for lengthy tarmac delays, which cut out most of those endurance tests. But airlines also stepped up their proactive change-fee–waiver game.

How Weather Waivers Work

Waivers are a good deal: Not only do passengers get a pass on the $200 fee, but they also can usually buy replacement tickets without paying whatever extra a new ticket might cost (and the new ticket, since it’s purchased at the last minute, is almost always significantly more).

Again, if you hear about bad weather heading your way, contact the airline to see if weather waivers are being offered so you can switch your tickets in advance. Ideally, you wont' be at the airport until skies are clear again.

In recent weeks we’ve seen plenty of waivers due to snow on the East Coast and ice storms in the Midwest. Currently, waivers are being extended to Alaska, American and United customers (plus others), thanks to severe weather on the West Coast and in Canada.

Restrictions: Change fees are waived (in most cases) only if certain conditions are met. These guidelines from United are typical:

  • Fee waivers apply to only to flights in or out of certain airports (and airlines will list them).
  • Ticket changes must be made by a certain deadline.
  • New ticket must be for travel between the same cities as the original fare.
  • New ticket must be for same cabin class.
  • You must fly by a certain date.

It’s not like you’re getting a free trip, exactly, because you can’t fly whenever you feel like it – and if the storm has messed up your plans to be somewhere on a particular day (for a wedding, say), you may be out of luck. But that’s when I’d get on the phone and ask nicely if they can bend some of the restrictions; maybe they can, maybe they can’t, but you won’t know if you don’t bother to ask.

What to Do if Weather Threatens Your Trip

Any time you plan to fly, start paying attention to weather reports and not just in winter; bad storms in summer can be just as disruptive and sometimes even more so. Then, get connected to your airline so you will know if weather waivers are being offered. If so, the airline will explain how to do this: It may require you to make a call to change tickets, or you may be able to do it online. But first, you have to hear about the waiver. Taking the following steps will help: 

  • Make sure your airline can reach you. If you purchased a ticket but were allowed to skip the part asking for your email and phone, go back and fill it in now. Airlines can’t let you know about problems if they can’t reach you.
  • Follow your airline on social media. Yes, the airline’s website will still report on travel alerts, but it’s passive. If you sign up to follow the airline on Twitter, the alerts will come to you. Follow it on Facebook, too, while you’re at it; many airlines update all social media first.
  • If you’re already at the airport. Get on the phone to call the airline even as you line up for the gate agent, and be polite. As I’ve heard more than one airline employee say, it’s easier to put yourself out for a courteous customer than the one who’s yelling at you.

If you're lucky, you'll never need a weather waiver. But now that you know about them, you can save yourself a lot of time and trouble by being proactive about potential weather delays.