KEYSTONE, Colo. — Unseasonably warm weather in the mountains has forced Keystone and Copper Mountain to postpone their openings, which had been set for Halloween.

Copper Mountain officials said Tuesday the warm weather prevented snow-making crews from creating a quality top-to-bottom run. The ski resort is planning to open Nov. 7.

Gary Rodgers, president and general manager of Copper, says “delaying opening day was a hard decision to make, but the quality of our snow surface and the experiences of our guests are most important.”

Keystone also announced Tuesday that its crews were having the same problems. The resort did not announce a new opening day.