INGEOMINAS reported that thermal images of the lava dome in Galeras’s crater were taken during an overflight on 11 December. The images revealed temperatures as hot as 530 degrees Celsius on the N side of the dome and temperatures near 80 degrees Celsius on the W side. Temperatures had declined compared to thermal images taken in October 2008. On 16 December, INGEOMINAS reported that during the previous few days, gas plumes rose to altitudes of 5.9-6.7 km (19,400-22,000 ft) a.s.l. and drifted NW.
Source: Instituto Colombiano de Geología y Minería – “Report provided courtesy of the Smithsonian’s Global Volcanism Program and the US Geological Survey’s Volcano Hazards Program.”