Fuegosta soils are on erosional fan remnants of fan piedmonts. These soils formed in alluvium from mixed rock sources, mainly volcanic tuffs with minor amounts of quartzite and limestone. Slopes are 2 to 8 percent. Elevations are 4,600 to 6,200 feet. The climate is semiarid with cool moist winters.
Summers are hot and dry with occasional convection storms.
These are the Tomel and Vigus soils. Tomel soils are loamy-skeletal. Vigus soils lack a duripan. The present vegetation is mainly Bailey greasewood, shadscale, spiny horsebrush, spiny menadora, ephedra, joshua-tree and galleta. These soils are not extensive.