AVO reported that on 24 December the Volcano Alert Level for Cleveland was raised to Advisory, and the Aviation Color Code was raised to Yellow, due to a persistent thermal anomaly near the summit visible on satellite imagery acquired the day before. The previous Alert Levels were listed as Unassigned. Cloud cover prevented observations during 25-27 December. The thermal anomaly was again detected on 28 December, but was absent the next two days. No current seismic information was available because Cleveland does not have a real-time seismic network.
Source: Alaska Volcano Observatory (AVO) – “Reports provided courtesy of the Smithsonian’s Global Volcanism Program and the US Geological Survey’s Volcano Hazards Program.”