Too often, we’re asking the wrong question about atmospheric rivers and climate change. It’s understandable as Californians are bracing for the next system, watching footage of the Pajaro River levee break, wondering what fails next. It’s not just Californians, either. Our atmospheric rivers don’t always stop at the Sierras. They can plow across the rest of the country, dumping more rain and snow when conditions are right, like they were earlier this week in the Northeast. This year’s storms have seemed worse than many people remember, and the data back that up: This winter we’ve set new records for snowpack,...