Flight cancellations neared 2,000 Monday afternoon as winter storms brew along the East Coast and in the Rocky Mountains.
Flight-tracking web site FlightAware.com showed the majority of cancellations so far at Philadelphia International, Newark, N.J., and New York's LaGuardia airports.
Delays have skyrocketed since early morning. There were fewer than 200 nationwide early Monday, but as of the afternoon that number rose to almost 3,000.
More than half of the country could receive snow this week starting today, as storm systems pose a triple-threat of winter weather. The East Coast should expect snow from Boston to Washington, D.C., today – with as much as 8 inches of snow falling this morning and into the early afternoon.
READ: Triple-Threat of Winter Weather Across US
A second storm developing in the Rockies should dump 5 to 10 inches of snow from Colorado to Iowa Tuesday, striking the East Coast one day later with another dose of winter weather – this time heaviest snow will be inland in the Northeast with rain, sleet and snow along the coast from Washington, D.C., to Boston.
A third storm is expected to strike across the country near the end of the week, bringing a potential Nor'easter next weekend. It's too early to tell if the third storm will materialize into anything significant.
Several airlines have issued flexible travel policies, waiving change fees for fliers affected by cancellations. Here are links to the major airlines' policies:
With reporting by ABC News' Daniel God and Max Golembo.