Maybe you missed it, but the last eruptive episode at Kīlauea in Hawai’i was messy. Thankfully, that messiness didn’t mean injuries and fatalities, but it does mean that suddenly a lot of people have to deal with cleaning up rocks. We just dealt with cleaning up 13″ of snow in Central Ohio, but snow will melt (eventually). When volcanic debris falls, it does not disappear on the next warm day and there might be longer term consequences. Clean up takes time.

The latest eruptive episode, on January 24 and the volcano’s 41st since summit eruptions resumed in December 2024, was a doozy. A confluence of a very tall lava fountain that reached nearly 500 meters (over 1,500 feet) and strong winds mean much of the fragmental debris (called “tephra”) ended up spreading across a wide area.

You can see in some of the images taken by Hawaiian Volcano Observatory staff during the eruption the chunks of ash, reticulite (think pumice, but dark), Pele’s hair and years and volcanic gases. These shots were taken relatively close to the eruption vent in the Halema’uma’u crater, but the map produced by HVO gets at the full extent of the fallout.

Basaltic ash (<2 mm) from the eruption spread over 40 kilometres to the north and east of the volcano while areas up to 10 kilometres to the east got covered in debris up to 64 mm (2.5 inches) across. This means the town of Volcano and many parts of Hawaii Volcanoes National Park had lots of debris fall!

Remember, even though it flew through the air, this is still rock. Cleaning up volcanic debris isn’t like shovelling your snowy driveway, even if it is relatively light. Local authorities reported that some areas saw multiple inches of volcanic debris (like in the photo below) come down during the episode. The injuries from the eruption came from people falling off their roofs trying to remove debris rather than any volcanic activity itself. It took multiple days for people to clean up their homes and property.

Luckily, water supplies for the national park are covered and protected from the ash and debris fall. However, the fine, glassy ash and Pele’s hair did leave to the shutdown of a local public pool as officials figure out how to clean out the filtration system.

This tephra fall is a first for many residents, but it is just one of the risks of living on top of an active volcano like Kīlauea.