San Francisco ? Southwestern Indian tribes are asking a federal appeals court to block the proposed expansion of the Arizona Snowbowl ski resort.

They say the plan for snowmaking using treated sewage on land that they hold sacred is an affront to their culture. Hopi attorney Scott Canty said it is up to the deities, not man, to make snow.

The resort is on the San Francisco Peaks that have spiritual and religious meaning to 13 tribes in the Southwest. To attract more skiers, the resort wants to add a fifth lift, spray manmade snow and tear down and groom about 100 acres of forest.