In 2008, the Tioga Road opened on May 21 and closed on October 30; the Glacier Point Road opened on May 2 and closed on December 12.

There is no estimated opening date for either of these roads. They usually open in late May or early June, conditions permitting.

Once plowing is completed, additional work must be completed before the road can safely be opened.

Factors affecting plowing operations:

• Avalanche zones (26 potential areas). The Olmsted Point avalanche zone requires a lot of work, including application of charcoal over the snow to help with melting and blasting the snow slab to make it safer for personnel.
• Heavy snow pack slows the whole operation.
• Trees that have fallen across the road and been buried in the snow. These can cause substantial damage to the equipment and result in a stop to all operations until they're cleared.
• Rock slides buried by the snow. These can cause substantial damage to the equipment and result in a stop to all operations.
• Snow storms during the opening require a stop to Tioga Road operations and in order to plow and sand the park roads.
• Road repairs and ditching and brushing operations once snow has melted back enough.

Watch a 3.5-minute video about plowing of the Olmsted Point avalanche zone. [7.7 MB Quicktime Movie (MOV)]