Kīlauea had two persistent lava lakes: one in the Halemaʻumaʻu vent cavity within the summit caldera, and another within the Puʻu ʻŌʻō cone located on the east rift zone of the volcano. In May 2018, both of these lava lakes disappeared as a result of increased activity in Kīlauea's east rift zone. However, the Hawaiian Volcano Observatory is certain that the Halemaʻumaʻu lava lake will eventually return.