Alaska Volcano Observatory

Beginning on March 17, 2021, AVO observed increased satellite detections of volcanic gas emissions and elevated surface temperatures at Cleveland volcano. In addition, a local earthquake occurred on March 10, large enough to measured on seismometers 100 km away on Umnak Island. These data indicate a potential for increased eruptive activity at Cleveland. In response, AVO raised the Aviation Color Code and Volcano Alert Level at Cleveland from UNASSIGNED to YELLOW/ADVISORY on March 20, 2021. Seismicity, gas emissions, and elevated surface temperatures subsided in the following months; AVO downgraded the Aviation Color Code and Volcano Alert Level at Cleveland to UNASSIGNED on October 20, 2021.