Balloons depicting classic cartoon characters are an iconic part of the Macy's Thanksgiving Day Parade. But they may be missing from this year's celebration. As CNN reports, the forecast for Thursday calls for wind gusts that exceed the safe limits for marching massive, helium-filled balloons through New York City, which means there's a good chance characters like Snoopy, Spongebob, and The Grinch won't leave the ground.

The Macy's Thanksgiving Day Parade has seen several mishaps in its 93-year history. In its first year, there was no plan in place for deflating the balloons when the parade ended, so handlers simply let them go and watched them pop in the air.

As the balloons got bigger, they became more dangerous. Four people were injured in 1997 when strong winds knocked the Cat in the Hat balloon into a streetlight, causing it to fall into the crowd below. The next year, legislators strengthened regulations around marching the floating behemoths down city streets.

New York City law states that oversized parade balloons must be grounded if sustained winds exceed 23 mph or if gusts exceed 34 mph. A recent forecast from the National Weather Service predicts winds of 25 mph and wind gusts of 38 mph along the parade route Thursday morning. An early forecast isn't enough to cancel the event's main attractions, but if wind speeds don't come down by Thursday morning, the balloons won't be allowed to fly.

Balloons are rarely grounded at the Macy's Thanksgiving Day Parade. It's only happened once before on an especially windy Thanksgiving day in New York City in 1971. Read up on more facts about the parade before it kicks off on Thursday, November 28.

[h/t CNN]