California has spent most of the past 15 years in drought, but 2015 was exceptional. The Sierra Nevada normally hits maximum snowpack for the year in early April, but by April 1, alpine meadows usually buried in 5 feet of snow were bare. The snowpack stood at just 5 percent of its average level. A September study of tree-ring records revealed the mountain range had not been this dry in at least 500 years. And yet for all its severity, this drought also has been one of paradoxes.