Aspen Mountain was closed last Thursday due to helicopter activity. A helicopter was flying above the mountain, transporting concrete infrastructure for a new lift.

The new lift in question is the Nell Bell lift, a project undertaken by Aspen Skiing Co. Further details about the project and the helicopter operation are available from the Aspen Daily News.

The mountain's closure was a result of the helicopter's presence, indicating that safety precautions were taken to ensure a smooth operation. For more information on the Nell Bell lift project and its progress, readers can refer to the Aspen Daily News.