INGEOMINAS reported that during 11-17 November gas plumes from Nevado del Huila were seen on the web camera rising 2.5 km and drifting downwind. Ash plumes sometimes accompanied the gas emissions on 12, 13, and 15 November. The Alert Level remained at II (Orange; "probable eruption in term of days or weeks"). Based on analyses of satellite imagery, the Washington VAAC reported that during 11-16 November thermal anomalies were seen intermittently through cloud cover.

Geological Summary. Nevado del Huila, the highest peak in the Colombian Andes, is an elongated N-S-trending volcanic chain mantled by a glacier icecap. The andesitic-dacitic volcano was constructed within a 10-km-wide caldera. Volcanism at Nevado del Huila has produced six volcanic cones whose ages in general migrated from south to north. The high point of the complex is Pico Central. Two glacier-free lava domes lie at the southern end of the volcanic complex. The first historical activity was an explosive eruption in the mid-16th century. Long-term, persistent steam columns had risen from Pico Central prior to the next eruption in 2007, when explosive activity was accompanied by damaging mudflows.

Sources: Servicio Geológico Colombiano (SGC), Washington Volcanic Ash Advisory Center (VAAC)