A small explosion at Cleveland was recorded by the seismic network at 1155 on 8 December.
A second small explosion with a higher peak amplitude was detected at 1153 on 12 December, prompting AVO to raise the Aviation Color Code to Orange and the Volcano Alert Level to Watch.
No ash cloud was observed, though weather clouds obscured views of the volcano.
Elevated surface temperatures were visible in satellite data on 15 December.
A small explosion which occurred at 0737 on 16 December generated a minor ash cloud that drifted NE.
Source: US Geological Survey Alaska Volcano Observatory (AVO)