Dec 31 (Reuters) - Holiday skiers at Utah's Park City, the biggest U.S. ski resort, reported on social media that they were encountering long lift lines and some closed trails on Tuesday as a strike by ski patrol workers entered its fifth day.

Nearly 200 ski patrol and safety workers are on strike over demands for higher pay at Park City Mountain Resort, which is owned by Vail Resorts Inc ( MTN ), demanding an entry-level base wage of $23 an hour, up from the current $21, according to an emailed statement from the ski patrol union.

This week is the busiest ski week of the year.

Park City remained open on Tuesday, and many of the ski patrol were still working, Vail Resorts ( MTN ) said in an emailed statement. The company said in an email that it does not disclose staffing figures.

The union, the Park City Professional Ski Patrol, said in its email that there are typically 120 people on patrol, but that on Tuesday there were between 30 and 35.

The union, in a post on social media, said Vail Resorts ( MTN ) had "flown in scabs" from other resorts to work at Park City.

Sara Huey, a spokesperson for Vail Resorts ( MTN ), said in an email that the company had met 24 of the union's 27 demands since the ski patrol's contract expired in April. She provided no specifics on the demands the company had not met.

Huey said Vail had increased ski patrol wages by more than 50% during the past four ski seasons, pushing the average hourly wage to over $25.

The 7,300-acre ski resort did not sell lift tickets this week, according to local media reports and a Park City employee who declined to provide their name, leaving the resort open only for annual pass holders.

Vail Resorts ( MTN ) operates more than three dozen ski resorts, including Vail and Breckenridge in Colorado, Whistler Blackcomb in British Columbia, Canada, and Stowe in Vermont.