Sand Creek Canyon was formed from layers of ash and pumice spewing from Mt. Mazama’s magma chamber before Crater Lake was formed. Water erosion has carved through up to 300 feet of deposited material to form the current stream corridor. In the 7,700 years since the eruption, the coarse sandy soils that developed are low in nutrients and water-holding capacity, presenting a challenging substrate for plant growth. Flowers such as Indian paintbrush, penstemon and buckwheat are also limited by a short flowering season, from mid-June through mid-September.