AVO reported that recent satellite images of Cleveland revealed that a lava dome has been extruded in the summit crater, with growth likely beginning after the last explosion on 31 March.
The Aviation Color Code was raised to Orange and the Volcano Alert Level was raised to Watch.
Slightly elevated surface temperatures were identified in satellite images over the past couple of weeks.
The new dome was first visible in images on 15 April, with the presence of a small (less than 10 m diameter) mound deep in the crater.
By 23 April this mound had grown to 45 m in diameter.
Dome growth had occurred with no detectable seismicity.
Source: US Geological Survey Alaska Volcano Observatory (AVO)