Severny Island

NASA

Fans of the Arctic

Editor’s Note: Today’s story is the answer to the July Puzzler. Call it an alluvial face-off. On the southern end of Severny Island in the Russian Arctic, rivers rush down from rugged terrain flanking a broad valley. Upon reaching flatter ground, the waters slow and distribute sediment into cone-shaped features called alluvial fans. Several appear in opposing orientations alongside a braided river…