In Idaho, BLM manages nearly 21,000 acres of public lands in the Sand Butte Wilderness Study Area. Sand Butte WSA is composed of an older lava flow covered by wind-deposited soils. The crater was formed by a violent explosion caused by the rapid generation of steam when erupting magma contacted ground water. Elevations range from 4250 feet, along the WSAs southern boundary, to 4974 feet at the summit of Sand Butte. Vegetation generally consists of sagebrush interspersed with grasses and forbs.