NEW YORK (WABC) -- Rehearsals got underway Monday for the Macy's Thanksgiving Day Parade amid the potential for high winds that threaten to ground the iconic balloons.
Broadway stars, celebrities and various performance groups will begin to prepare for the annual event, which is broadcast to millions around the nation.
But there are worries over the weather's impact on the parade, as under New York City law, balloons cannot fly if sustained winds exceed 23 miles per hour or if gusts are stronger than 34 miles per hour.
If it is too windy, the balloons will be grounded and walked through the streets.
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Back in 1997, on a very blustery Thanksgiving Day morning in New York City, the iconic Cat in the Hat balloon got caught up in some strong wind gusts.
The balloon handlers couldn't control it and it blew into a lamppost, injuring four spectators.
In 1993, an off-duty police officer was struck after Sonic the Hedgehog hit a light post. The officer's shoulder was broken.
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There were also injuries from an incident in 2005 in which a huge M&M balloon bounced off a building and hit a light pole, tearing part of the pole down. An 11-year-old girl and her 26-year-old sister suffered chipped teeth and cuts that needed stitches, as well as bruising.
After the 1997 and 2005 accidents, the new safety strategies were adopted.
Aside from the years the parade was canceled completely due to bad weather, the balloons have only been grounded once -- back in 1971. Officials with the parade made the assessment that it was too dangerous to fly the balloons, even before the city ever placed a rule on the balloons grounding criteria.
Macy's issued the following statement about weather-related planning:
"We are always attuned to weather conditions for the Macy's Thanksgiving Day Parade. We monitor the weather on a daily basis, but at this time, it is too early to make any determinations regarding the flight of the parade's giant balloons, as we use on the scene data versus forecasts. The parade takes place rain or shine. We have a number of weather operations in place, which include continuous monitoring of conditions on site by a licensed meteorologist, who is also in direct communication with the National Weather Service. Along the parade route, there are several weather monitoring stations. In addition, the assistant pilot on each giant balloon carries a wind meter, which is also monitored by an NYPD representative. Based on the city's guidelines, no giant character balloon will be operated when there are sustained wind conditions exceeding 23 mph and wind gusts exceeding 34 mph. On parade morning, Macy's works closely with the NYPD, who, based on the current weather data and the official regulations determine if the balloons will fly and at what heights. Each is designed to fly at different heights and angles based on their shape and scale and the exact wind conditions along the route. The decision on adding the balloons to the lineup is made just prior to the start of the parade and takes into account the weather data along the entire parade route and information from nearby weather stations."
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Rehearsals begin as wind threatens Macy's Thanksgiving Day Parade