When it rained rocks: tephra fall during Kīlauea's episode 41 — Volcano Watch

Large lava fountains streamed from both the north and south vents reaching heights of at least 1475 feet (450 meters) during episode 41 of Kīlauea’s summit eruption on January 24, 2026.  Strong updrafts coupled with light winds blowing to the east and north sent lava fragments from the fountains, called tephra, over much of the District of Puna and into South Hilo and the eastern edge of Kaʻū.

This map shows the tephra fall associated with episode 41 of Kīlauea's episodic summit eruption, on January 24, 2026. Tephra is a generic word for any material erupted by a volcano that travels through the air before landing on the ground. During episode 41 on January 24, lava fountains from the north and south vents in Halemaʻumaʻu at the summit of Kīlauea reached up at least 450 m (1475 feet). Weak surface winds in combination with stronger upper-level winds blowing to the east and north resulted in widespread tephra fall in communities to the northeast and east within the Districts of Kaʻū, Puna, and South Hilo. 

Tephra fallout was densest within 5 miles (8 kilometers) east-northeast of the vents in Halemaʻumaʻu crater. A thick tephra layer covered the summit region of Hawaiʻi Volcanoes National Park and parts Volcano Village and Mauna Loa Estates adjacent to the National Park. The ground in these areas was completely or nearly completely blanketed with pieces of tephra that was so thick in areas that road markings were not visible to drivers. 

Tephra fragments ranged in size from small strands of Pele’s hair to larger pieces of frothy and lightweight reticulite that were up to a foot (30 cm) in diameter. They cooled quickly as they traveled through the air and many broke or shattered upon impact with hard surfaces. Others drifted down and landed intact on softer surfaces, like grass, while some pieces remain suspended in the branches of trees and ferns.  

Farther away, parts of the Volcano Golf Course Community, Ohia Estates, Royal Hawaiian Estates, and Fern Forest received tephra fall ranging from Pele’s hair and ash to pieces of reticulite that were up to several inches (64 mm) in diameter. 

Communities even farther away, in the District of Puna and parts of South Hilo, saw light fall or a dusting of fine-grained ash and Pele’s hair, extending from Pepeekeo to Kalapana. 

What made this tephra fall pattern from episode 41 so different from earlier episodes?

Several past episodes have had lava fountains reaching similar heights, but never from both vents at the same time. And most past eruptive episodes were erupted during trade wind conditions. 

Trade winds blow from northeast to southwest. When there are lava fountaining episodes at the summit of Kīlauea during trade winds, tephra is transported to the southwest. Much of the larger pieces land in the closed area of Hawaiʻi Volcanoes National Park but communities in the District of Kaʻū, including Pāhala, Nāʻālehu, and Ocean View, have experienced ash and Pele’s hair falling on them several times.

During episode 41, there were no trade winds. Winds at the ground level were weak. As the dual high fountains from the north and south vents erupted large volumes of lava, they released an immense amount of heat that rose upwards, lofting tephra ranging in size from fine ash and Pele’s hair to the larger frothy reticulite being formed by the lava fountains. At upper levels, these lightweight clasts encountered stronger winds blowing to the east and northeast, transporting them in that direction. 

Tephra landed on Highway 11 as vehicles were driving on it, creating hazardous conditions. The County of Hawaiʻi temporary closed Highway 11 in two locations on either side of the entrance to Hawaiʻi Volcanoes National Park. Within Hawaiʻi Volcanoes National Park, visitors were pelted by falling tephra as rangers temporary closed the public overlooks around the caldera. Episode 41 started at 11:10 a.m. on January 24, and the most intense period of tephra fall happened in the hours immediately after the episode started. Lighter tephra fall continued until the episode ended more than 8 hours later, at 7:26 p.m. 

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Volcano Watch is a weekly article and activity update written by U.S. Geological Survey Hawaiian Volcano Observatory scientists and affiliates.