NEW YORK (AP) — Thanksgiving travelers are scrambling to book earlier flights to avoid a sprawling storm bearing down on the East Coast. And high winds are threatening to ground giant balloon versions of Snoopy and SpongeBob SquarePants in the Macy’s parade.

The inflatable characters that soar through Manhattan may not lift off Thursday if sustained winds exceed 23 mph and gusts exceed 34 mph. That’s according to city rules enacted after fierce winds in 1997 injured a spectator.

Current forecasts call for sustained winds of 20 mph and gusts of 36 mph. Macy’s says it’s too early to decide the fate of the giant balloons.

Meteorologists warned that the storm would almost certainly upset holiday travel plans on Wednesday for those hoping to visit loved ones in the mid-Atlantic and Northeast.