The Colorado River Basin’s 20 years of drought and the dramatic decline in water levels at the river’s key reservoirs have pressed water managers to adapt to challenging conditions. But even more extreme — albeit rare — droughts or floods that could overwhelm water managers may lie ahead in the Basin as the effects of climate change take hold, say a group of scientists. They argue that stakeholders who are preparing to rewrite the operating rules of the river should plan now for how to handle these so-called “black swan” events so they’re not blindsided.