Planes: Nearly 2,600 flights are canceled and 3,800 are delayed, affecting airports from Washington to Boston, Flightaware.com reports. Several airlines announced they were waiving ticket changes and cancellation fees for fliers traveling to and from airports up and down the Northeast and Chicago. If your flight is canceled or significantly delayed, you can get a refund.
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Check with your airline's website for which airports qualify. Look for breaking information in their Twitter feeds. And remember that tweeting at the airline can be a way to get a quick fix, especially if phone lines get jammed like last time.
(Read more: Propane shortage may leave millions in US shivering)
It will likely take days to unwind the fallout from the storm. Plan accordingly. Already 537 flights for Wednesday were canceled.
Trains: So far Amtrak reports no changes to service, but this morning the railroad tweeted a recommendation that travelers check their train status before they leave home. Metro-North warned travelers that service could be suspended or reduced during rush hour.
Automobiles: Expect a treacherous commute. Get out early if you can and then stay off the roads as conditions will only worsen. By nightfall, near-blizzard conditions along the coast are possible.
—By Ben Popken of NBC News