Scientists Monitoring 185°F Volcanic Lake for Steam Explosions

Scientists at the U.S. Geological Survey (USGS) have been monitoring a super-heated lake in Hawaii since July, 2019. The lake is at the summit caldera of the active Kīlauea volcano, and is, in some places, roughly as hot as a pan on a stove. The USGS scientists are specifically watching for potential upcoming hazards, which include “steam-blast explosions” amongst others.

The Sacramento Bee reported on the effort to monitor the steaming lake, which began forming after Kīlauea’s 2018 eruption. According to NASA, the eruption poured lava from fissures into the caldera—a caldera is a volcanic crater—causing part of its floor to collapse. The collapse resulted in a hole almost as deep as One World Trade Center is tall.

While the new, giant hole was quiet at first, helicopter pilots began to notice water pooling inside of it last year. Since then, the water levels have been rising, and today, the lake is larger than five football fields across and 100 feet deep in some places.

Scientists are watching a 185-degree-Fahrenheit lake in Hawaii for steam-blast explosions.


The USGS provides a time-lapse video of the caldera lake in the tweet above. Overall, the lake has a rusty brown coloration, although there are greenish spots. As the USGS notes, those greenish spots are where the lake is hottest. And those spots are indeed very, very hot.

Using high-resolution thermal imagining cameras, the USGS has been able to determine that some parts of the lake are 185 °F. (For reference, the average temperature of a pan on a “low setting” burner is roughly 195 °F.) Globally, the USGS says, there are very few volcanic lakes with a surface temperature above 176 °F.

Scientists are watching a 185-degree-Fahrenheit lake in Hawaii for steam-blast explosions.


The USGS has attributed the lake’s heat to several possible causes. One likely catalyst for the water’s heat is hot rubble at the base of Halema‘uma‘u, a pit crater within the much larger summit caldera. Another possible factor may be nearby gas vents (or “fumaroles”) that heat up to 302 °F.

The scientists are watching the lake closely because they’re concerned about the potential hazards it poses. “At several other volcanic lakes around the world, changes in lake temperature have preceded explosions,” the USGS says. One of the main concerns is the possibility of “steam-blast explosions,” also referred to as “littoral” explosions. These steam-blast bursts happen when water is violently flash-boiled into steam by hot materials, including magma. Below is a video of steam-blast explosions occurring.

Moving forward, the USGS says it will continue to monitor the piping-hot caldera lake. The agency will specifically be looking for changes in the lake’s temperature, which may proceed a violent event. As of now, the USGS says the lake’s temperatures have remained steady and do not show signs of significant change.

What do you think about this super-heated volcano lake in Hawaii? Are you having Dante’s Peak flashbacks now, or are you just suddenly in the mood for ramen? Let’s get into some hot water in the comments, people!

Feature image: USGS