Hundreds of musicians scheduled to perform at the 25th New Year's Day parade in London face a race against time to fly to the UK after they were grounded by blizzards in the US.
Around a thousand American musicians and cheerleaders had their flights cancelled after more than a foot of snow fell in the north east of the country.
The wintry conditions brought the east coast to a standstill with Heathrow Airport warning flights to and from North America may be cancelled or delayed.
Organisers of the 25th anniversary London Parade called on airlines to help get the student bands to the UK in time for the event.
The groups stranded account for around a quarter of those taking part in the New Year's Day celebrations.
Bob Bone, executive director of the New Year's Day Parade, said: "We are totally in the airlines' hands - and some are proving to be less than helpful.
"These performers have been saving for at least two years to make the trip and we are imploring the airlines to realise that they are not here for a holiday - but to live their dreams and entertain the world.
"Airline rules might preclude them from being rebooked in time to make the trip - we can only urge carriers to show some heart and help make this trip happen."
One of the stranded parties is a 300-strong band from James Madison University in Virginia while groups from Mount Desert High School, Maine, and the Maryland Classic Youth Orchestra were also grounded.
Corning Painted Port High School from New York state and Briar Woods High School and Dulaney High School from Maryland were among those battling to make the trip and hundreds of cheerleaders were stuck at Newark, John F Kennedy and Boston airports.
More than 500,000 people are expected to turn out in Westminster on Saturday for the parade, which follows a 2.2-mile route from the Ritz Hotel through Lower Regent Street, Trafalgar Square and Parliament Square. A message from the Queen will be read out at the start of the event.
Airlines warned normal service would not resume until at least tomorrow as New York City's airports were closed today.
British Airways said most flights to and from Boston, New York, Philadelphia and Washington were cancelled or delayed.
Meanwhile, Heathrow Airport was fully open today after temperatures warmed up across the UK.
After sub-zero temperatures in the run-up to Christmas, south-west Cornwall was expected to see the mercury rise to 10C (50F) while the rest of the country enjoyed temperatures above freezing.
Clare Allen, forecaster with MeteoGroup, PA's weather division, said: "Today, it's feeling a lot less cold. We've got a band of rain, sleet and snow crossing the country and that's gradually fizzling out.
"There will be further snow in eastern areas of England in the early hours and that will clear to leave sleet, rain and drizzle."