By late summer, the snow has melted completely from the surface of lower Knik Glacier, exposing the rippling seracs of flowing ice covered in silt that has been carved from the surrounding mountains over millennia. This view—where the medial moraine defines the merging of two glacial lobes—reminds me of a winding country road. In the far distance, you can see the tip of Lake George Glacier, above where it meets the Knik, and close to where they both feed the Knik River in its rush to the sea. More than 20 million tons of pulverized bedrock and sediment flow into Knik Arm each year, most of it ground off these mountains and then carried by the Knik River. The mud flats of Cook Inlet owe their existence to the erosive power of this immense glacial conveyer belt.