Invasive mussels are aquatic hitchhikers. They have spread across the U.S. by attaching to watercraft and getting a ride to lakes and reservoirs. Boat inspection stations like this one in Ravalli, MT are an essential firewall to prevent further infestation, but the hours are long and staffing is thin. Crown Project reporter Beau Baker hung out at the Ravalli station, which is just south of Flathead Lake. Listen to his audio postcard at our Crown Tumblr site.