Alaska Volcano Observatory

On April 25, 2025, the Alaska Volcano Observatory raised the alert level/color code to YELLOW/ADVISORY, stating: "A small, short-lived explosion was detected at the Atka volcanic complex this morning at 10:34 AKDT April 25 (18:34 UTC April 25) in local infrasound and seismic data. Processing of the local infrasound data indicates the explosion originated from the summit crater of Korovin, one of several volcanoes within the Atka volcanic complex. AVO is increasing the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY.
"High clouds blocked the area at the time of the explosion, preventing satellite observations. Similar past events at the Atka volcanic complex did not result in a noticeable ashfall or ash cloud or other impacts.”
On May 5, 2025, AVO returned the alert level and color code to GREEN and NORMAL, stating: "No further explosive activity has been detected at the Atka volcanic complex since the small explosive event at 10:34 AKDT on April 25 (18:34 UTC on April 25). Thus, the Aviation Color Code and Alert Level are being reduced to GREEN/NORMAL.
"Brief explosive events at Korovin Volcano can occur without significant precursory unrest. Fallout of ash is unlikely to extend much beyond the upper flanks of the volcano. Possible ash clouds generated by such events are expected to be small and dissipate quickly."