When California water officials assess the drought, the first place they look is the northern Sierra Nevada mountains.

Rain and snowmelt from the area feed into a complex system of rivers, canals and reservoirs that send water across the state. And by almost all measures, the drought picture in Northern California has dramatically improved over the last two months, as a series of storms have helped replenish the state’s two major water projects. So far this season, rain levels in the northern Sierra are 180% of average, with 23.5 inches of rain falling — and more on the way this week.