As snow covered the British capital on Sunday, Heathrow Airport, one of the busiest in the world, was forced to ground dozens of flights. Airlines canceled flights and travelers reported waiting for hours in line to speak to airline representatives or on the tarmac as flights were not permitted to depart.

Heathrow Airport posted an update to Twitter early Monday saying that disruptions would continue today. The airport reported that some crew and planes were displaced following yesterday’s weather, leading many airlines to cancel flights for a second day. Heathrow, as well as other London airports—London City and Luton—have advised passengers to check their flight status before traveling to the airport.

According to FlightAware, 130 flights—or 19% of those scheduled to leave from London Heathrow Monday—have been canceled. Another 42 are delayed, and 111 flights headed to Heathrow have been canceled, with an additional 64 delayed.

London’s Evening Standard reports that as many as 50,000 British Airways passengers were stranded worldwide due to delays in de-icing planes Sunday. Around 27,000 of these were stuck in London. With a reported 70 short-haul and nine long-haul flights canceled Monday, The Independent estimates an additional 15,000 people will be affected.

The snowfall and freezing temperatures in London affected American travelers as well. An inbound British Airways flight from New York was forced to land in Dublin, while three other New York-bound flights were canceled. Flights originating from and headed toward U.S. airports in cities such as San Francisco, Los Angeles, New York, and Washington D.C. have been canceled according to FlightAware.

For passengers with travel reservations on Sunday or Monday, British Airways is giving them the option to re-book on alternate flights up to Monday, December 18, free of charge.