LAS VEGAS (KLAS) — Treacherous winter conditions across the country are disrupting holiday travel and causing hundreds of airline flight delays and cancellations.

Nearly 4,997 flights nationwide were canceled by 2:30 p.m. Friday and that number is expected to grow. Harry Reid International Airport was showing at least 147 flights canceled, according to FlightAware, a flight tracking website.

Departure board for Harry Reid International Airport. (Credit: Reid Int’l Airport)

Travelers can check Reid International Airport’s flight arrivals and departures at this link. Airport officials urge travelers to arrive at the airport at least two hours prior to the flight departure time and to expect large crowds.

“So far, parking remains open, Terminal 1 and long term is what we expect to close first, this being Friday, a holiday weekend, people will start to come in and that will reach capacity,” Reid International Airport Public Information Officer Joe Rajchel said. “We encourage people to go directly to Terminal 3, park at the long term there, and go through the checkpoint there, or if they have to check a bag come back to T1.”

Southwest Airlines canceled 921 flights Friday morning and more than 850 are showing delayed, according to FlightAware. The airline has a link for passengers to rebook trips if flights are canceled.

Most of the major airlines such as American, Delta, United, and Jet Blue are offering to waive change fees and fare differences if passengers choose to rebook their flights to avoid traveling in bad weather.

The airports with the most cancellations and delays Thursday were Seattle’s Tacoma International, Chicago’s O’Hare International, Denver International and LaGuardia.

Harry Reid International Airport is warning travelers that parking will be in high demand, especially in Terminal 1 and the Long Term garage. There are some tips on where to park at this link. You can also call (702) 261-5122 to get up-to-date parking information.

If wheelchair assistance is needed, that should be done in advance. You can get more information at this link.