Additional capacity restrictions and limited open terrain are causing headaches at ski areas across Summit County, leading to canceled reservations at Breckenridge Ski Resort this weekend.

Vail Resorts officials announced the cancellations in a letter that notified employees their passes would not be valid this weekend at Beaver Creek, Breckenridge, Keystone Resort or Vail Mountain.

The letter informed workers that challenging conditions have limited the resort’s ability to open terrain and accommodate the number of guests planned for the weekend of Dec. 12-13.

Employees are not required to use the reservations system, and this weekend’s employee pass restriction was acknowledged in the letter as an unforeseen and difficult decision by Vail Resorts management.

“Please note we had to cancel a limited number of guest reservations at Breckenridge as well,” the letter stated. “As many of you know, restricting employee passes is something that has happened in prior years as well when we do not have enough terrain open in the early season, but we understand it is disappointing any time it’s necessary.”

Tuesday, Dec. 8, marked the beginning of the core season, which runs through April 4. During this period, passholders are permitted to make seven priority-day reservations at a time. Those advance reservations are now coming into play on the daily calendar, meaning fewer week-of reservations remain to be booked.

Vail Resorts also has changed its week-of reservation system, opening reservations for a new day at midnight each night. Previously, reservations would open on Wednesday afternoons for the following week.