HVO/USGS Volcanic Activity Notice Volcano: Kilauea

HVO/USGS Volcanic Activity Notice

Volcano: Kilauea (VNUM #332010)

Current Volcano Alert Level: WATCH
Previous Volcano Alert Level: ADVISORY

Current Aviation Color Code: ORANGE
Previous Aviation Color Code: YELLOW

Issued: Monday, April 20, 2026, 9:16 PM HST
Source: Hawaiian Volcano Observatory
Notice Number: 2026/H186
Location: N 19 deg 25 min W 155 deg 17 min
Elevation: 4091 ft (1247 m)
Area: Hawaii

Volcanic Activity Summary:

Precursory low-level activity for episode 45 of the ongoing Halemaʻumaʻu eruption at the summit of Kīlauea began around 7:46 p.m. HST on April 20, 2026, with several overflows of lava from the north vent. Accordingly, HVO is raising the Alert Level for Kīlauea from ADVISORY to WATCH and the Aviation Color Code from YELLOW to ORANGE. Alert level and aviation color code definitions: https://www.usgs.gov/programs/VHP/alert-level-system.

Low-level precursory activity can continue for hours to days before Kīlauea summit lava fountaining begins. The forecast for lava fountaining episode 45 to start is between April 21-26. Another VAN will be published when lava fountaining begins.

• All eruptive vents and lava flows are confined to Halemaʻumaʻu crater within Hawaiʻi Volcanoes National Park. Tephra fall from volcanic ash clouds is greatest within 3 miles (5 km) of the vents, lighter ash and Pele’s Hair may stay suspended for large distances from the vents.
• Support science and community awareness by reporting tephra fall: https://hawaiiash.science/report_form
• Three Kīlauea summit livestream videos that show eruptive lava fountains are available here: https://youtube.com/@usgs/streams
• KPcam and MKcam provide views of the plume height for aviation purposes
• Additional short updates as the episode progresses will be posted here: https://www.usgs.gov/observatories/hvo/observatory-messages
• Timeline of eruptive episodes since December 23, 2024: https://www.usgs.gov/volcanoes/kilauea/science/eruption-information

Most lava fountaining episodes since December 23, 2024, have continued for a day or less.

Remarks:

Hazard Analysis: 

Volcanic Gas: water vapor (H₂O), carbon dioxide (CO₂), and sulfur dioxide (SO₂) are continuously released during an eruption. SO₂ reacts in the atmosphere to create the visible haze known as vog (volcanic air pollution) downwind, which may cause respiratory and other problems. Further information on vog can be found at https://vog.ivhhn.org/

Tephra: small glassy volcanic fragments—volcanic ash, pumice, scoria, Pele’s hair and reticulite—are created by the lava fountains. A combination of fountaining dynamics and wind conditions determines where tephra fall may occur for any given eruption episode. Larger particles fall near the vents while light particles may be wafted greater distances. These particles may be remobilized during windy conditions following recent eruptive episodes. Residents and visitors should minimize exposure to these fragments, which can cause skin, eye, and respiratory irritation. More information and guidance on tephra fall hazards is available at https://seagrant.soest.hawaii.edu/resource-and-guidance-for-volcanic-tephra-fall/

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 exist around Kīlauea caldera from Halemaʻumaʻu crater wall instability, ground cracking, and rockfalls that can be enhanced by earthquakes. Close to the vents, the tephra material on the crater rim is prone to cracking, slumping, and small landslides that sometimes expose hot and molten material within. 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.