The phantom cascades

New Hampshire's actual tallest waterfall

Mountains become treacherously iced-up at the height of winter. Cities can transform into concrete kilns during the summer. But we’ll always have waterfalls. Or will we…?

Whether they’re gushing like a thousand burst pipes or frozen into an ornate sculpture, there’s a presumed permanence to cascades. And to be sure, many of New England’s waterfalls are b…