spring in yellowstone national park: grotto geyser & rocket geyser vent in upper geyser basin as early evening shadows close in

background basin blue caldera close clouds day early environment erupt evening feature forest geology geothermal geyser geyserite grass green grotto group horizon hot hydrothermal landscape late national natural nature nps outdoor panorama park rocket scenery scenic shade shadows sinter sky spring steam thermal tourism travel trees upper vapor vent venting view volcano water wyoming yellowstone