late spring in yellowstone national park: churning caldron muddy pool in the mud volcano area along the grand loop road

area background bubbling caldera caldron cauldron churning clouds day environment evergreen feature forest geology geothermal grand grass green hill horizon hot hydrothermal landscape late loop mud muddy national natural nature nps outdoor panorama park pool road roiling scenery scenic sky spring springtime steam sunny thermal tourism travel trees vapor view volcano water wilderness wyoming yellowstone