The Colorado River has a long journey. It flows from mountains, runs by cities, winds through remote, rust-colored canyons and touches seven states before entering Mexico. It’s a natural wonder, but also a life source of the more than 30 million people who rely on it.

But in recent years, the Colorado River has become less reliable. Since 1999, abnormally low precipitation totals and hot and dry conditions have brought reservoir water levels close to record lows. The multiyear drought, the most severe since documentation began more than 100 years ago, has put the water supply in the thirsty Southwest in jeopardy.

This year, heavy snowpack and spring precipitation have brought the region some relief by partially refilling the reservoirs. But while National Oceanic and Atmospheric Administration research shows that snowmelt runoff into the upper basin hasn’t been this high since 1986, the southern end of the Colorado River continues to stop shy of the Sea of Cortez, where it used to run until the late 1990s.

The paradox is that this season stands in such stark contrast to the past 11 years of drought, highlighting the types of variability that climate change can wreak on the hydrological cycle.

‘It’s not at all uncommon […]