http://www.nps.gov/yose/planyourvisit/tioga.htm
Tioga Road progress for May 8, 2008
Ending Location: Tioga Pass
Average Snow depth: 6 feet (8 to 9 feet at Tioga Pass parking lots)
Snow removal operations continue, including widening Tioga Road and working on utility roads and spur roads. Four avalanche zones remain.
There is no estimated opening date for the Tioga Road.
The Glacier Point Road opened on May 2.
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.