Mess Lake Lava Field black young basalt. Its westernmost and southwesternmost ends are flanked by the Mess Creek Escarpment, forming a steep prominent cliff. This cliff exposes several layers of black columnar basaltic lava flows with distal rock fragments and pyroclastic deposits. Eruptions of the young Mess Lake Lava Field basalts cascaded down this steep lava cliff similar to what occurs at the island of Hawaii and covered some of the columnar basalt jointing. Near Mess Lake, inactive hot springs can be found and are most likely associated with the most recent eruptive activity in the Mess Lake Lava Field. Hot springs are closely
Lava buried by the advancing flow. This produces a layer of lava fragments both at the bottom and top of an aā flow. Accretionary lava balls as large as are common on aā flows. Aā is usually of higher viscosity than pāhoehoe. Pāhoehoe can turn into aā if it becomes turbulent from meeting impediments or steep slopes. The sharp, angled texture makes aā a strong radar reflector, and can easily be seen from an orbiting satellite (bright on Magellan pictures). Aā lavas typically erupt at temperatures of . The word is also spelled "aa", "aa", "aa", and "a-aa", and pronounced .