HVO/USGS Volcanic Activity Notice Volcano: Kilauea
HVO/USGS Volcanic Activity Notice
Volcano: Kilauea (VNUM #332010)
Current Volcano Alert Level: WATCH
Current Aviation Color Code: ORANGE
Issued: Wednesday, November 26, 2025, 12:25 AM HST
Source: Hawaiian Volcano Observatory
Notice Number: 2025/H513
Location: N 19 deg 25 min W 155 deg 17 min
Elevation: 4091 ft (1247 m)
Area: Hawaii
Volcanic Activity Summary:
Episode 37 of the ongoing Halemaʻumaʻu eruption ended abruptly at 11:39 p.m. HST on November 25 after 9.2 hours of continuous fountaining.
The north vent stopped erupting at approximately 11:39 p.m. HST marking the end of episode 37. No lava fountains or flows erupted from the south vent during episode 37. Dual lava fountains from the north vent reached maximum heights of 500-600 ft (150-180 m). Continuous fountaining lasted for 9.2 hours and produced an estimated 8.2 million cubic yards (6.3 million cubic meters) of lava. The combined average eruption rate was over 200 cubic yards per second (190 cubic meters per second). Lava flows from the fountains covered about 75% of the floor of Halemaʻumaʻu crater.
The eruptive plume reached heights of more than 14,000 ft (4,200 m) above sea level during episode 37. Volcanic gas emissions greatly decreased after lava fountaining ended.
The Uēkahuna tiltmeter (UWD) recorded about 16.5 microradians of deflationary tilt during episode 37. The end of lava fountaining was coincident with a rapid change from deflation to inflation at the summit and a decrease in seismic tremor intensity.
Lava flows from this episode on the floor of Halemaʻumaʻu within the southern part of Kaluapele (Kīlauea caldera) may continue to exhibit slow movement or incandescence as they cool and solidify over the coming days.
Most episodes of Halemaʻumaʻu lava fountaining since the eruption started on December 23, 2024, have continued for around a day or less and have been separated by pauses in eruptive activity lasting generally at least several days.
- Timeline of eruptive episodes since December 23, 2024: https://www.usgs.gov/volcanoes/kilauea/science/eruption-information
- Three Kīlauea summit livestream videos are available here: https://www.youtube.com/@usgs/streams
No changes have been detected in the East Rift Zone or Southwest Rift Zone.
Kīlauea Volcano Alert Level/Aviation Color Code remain at WATCH/ORANGE. All current and recent activity is within Hawaiʻi Volcanoes National Park.
Recent Observations:
[Volcanic cloud height] Unknown
[Other volcanic cloud information] Sulfur dioxide emission rate is typically 1,200-1,500 tonnes/day between eruptive episodes
[Ballistics] N/A
[Lava flow/dome] N/A
[Lava flow] N/A
Hazard Analysis:
[General hazards] Pele’s hair and tephra may affect areas downwind of eruptive vents
[Ash cloud] N/A
[Ashfall] N/A
[Lava flow/dome] N/A
[Pyroclastic flow] N/A
[Mud flow] N/A
[Volcanic gas] Usually 1,200-1,500 tonnes/day SO2 between eruptive episodes
[Lava flow] May continue to exhibit slow movement or incandescence as the cool and solidify over the coming days
Remarks:
Hazard Analysis:
This episodic eruption is occurring within a closed area of Hawai’i Volcanoes National Park. High levels of volcanic gas—primarily water vapor (H2O), carbon dioxide (CO2), and sulfur dioxide (SO2)—are one hazard of concern, as this hazard can have far-reaching effects downwind. As SO2 is continuously released from the summit during an eruption, it will react in the atmosphere to create the visible haze known as vog (volcanic smog) downwind of Kīlauea. SO2 and vog may cause respiratory and other problems at high concentrations. Further information on vog can be found at https://vog.ivhhn.org/
Another hazard closer to the vent is fallout of Pele’s hair and other volcanic fragments from lava fountains. Pele’s hair is strands of volcanic glass often produced by lava fountaining activity and can be carried well over 10 miles (15 kilometers) from the vent. Other hot glassy volcanic fragments including Peleʻs hair, volcanic ash, pumice, scoria, and reticulite can fall on the ground within 1-2 miles (1-3 kilometers) of the eruptive vent(s) with the highest concentrations downwind of the vent(s). Pumice and other volcanic fragments have fallen on Highway 11 west of Hawaiʻi Volcanoes National Park depending on wind and eruption conditions. Strong winds may waft light particles, including Pele’s hair, to greater distances downwind. Once they are on the ground, Pele’s hair can sometimes cluster and tangle together, giving it the appearance of a tumbleweed. The extent of Pele’s hair deposition is dependent on lava fountaining activity and current wind conditions. Residents and visitors should minimize exposure to Pele’s hair and other glassy volcanic fragments, which can cause skin and eye irritation. More information about how Pele’s hair, its hazards, and what to do is available here: https://www.usgs.gov/observatories/hvo/news/volcano-watch-recent-lava-fountains-highlight-peles-hair-hazards. A recently updated Frequently Asked Questions document that includes information about potential health effects of Pele’s hair is available here: https://vog.ivhhn.org/sites/default/files/PelesHair_FAQs_v2.pdf
Hawaiian lava flows generally advance slowly downslope, and during this eruption flows have been confined to Halemaʻumaʻu crater and the southwest side of Kaluapele, Kīlauea’s summit caldera.
Other significant hazards also remain around Kīlauea caldera from Halemaʻumaʻu crater wall instability, ground cracking, and rockfalls that can be enhanced by earthquakes within the area closed to the public. This underscores the extremely hazardous nature of Kīlauea’s caldera rim surrounding Halemaʻumaʻu crater, an area that has been closed to the public since late 2007.
