[3] It is located inside a volcanic rim, which is roughly 500 feet (150 m) above sea level, making it the highest point on the peninsula.

[5] Much of the crater is forested, containing many types of shrubs and trees, such as the wiliwili, a plant native to the area, but mostly non-native plants, including invasive Schinus terebinthifolia (Brazilian peppertree) and Lantana camara (big-sage).

A survey observed that black rats in the area were destroying certain native plants in the crater, particularly the endemic tree species Reynoldsia sandwicensis.

[8][7] The lake's water quality is inspected by the National Park Service 4 times a year, which has occurred since 2009.

It is believed that this event occurred either due to a drought that caused the surface water, which contained a large amount of oxygen, to evaporate, or because of a landslide.

A few days later, on December 14, the lake was covered in a green layer of phytoplankton due to a heavy rain the last 48 hours.