The process of the volcanic activity of  Tungurahua is quite different to that of Pichincha. The volcano emits continuously ashes, smoke and lava (Strombolian activity). Magma rises up the chimney and reaches the opening of the volcano. The danger of a big eruption lies in the blockage of the exit vent by big boulders and other materials. If it cannot exit freely anymore, there is a chance that more and more pressure accumulates under the blockage and finally leads to a huge explosion with potential structural collapse. Should that happen and the peak should break away, then a huge catastrophe is at hand as Baños and the other surrounding villages will be completely destroyed and some 20 000 people are in danger of losing their lives (see below story of evacuation).

In the middle of October 1999, when the danger level was raised from yellow to orange alert, the government started to evacuate the people living in the vicinity of the volcano. More then 20 000 persons, including all the inhabitants of Baños, a tourist town located at the foot of the colossus, were moved to shelters in nearby larger cities, in particular to Ambato, the capital of the province. All roads leading to the vicinity of Tungurahua were closed and patrolled by the military. That interrupted a major access to the Amazon like the Ambato - Puyo highway. Baños appeared to be a ghost town with no apparent life although a few people stayed back, hidden away in the church and their houses. Others also bypassed the military controls to tend to their farms and many more began to clamor soon for a return to their homes and businesses. Then, just before Christmas of 1999, the tensions came to a violent conclusion as protesters confronted the military, claiming one life in the clashes. After those events the authorities let the people return at their own risk although nothing really changed yet in the danger.

Lahars almost completely destroyed the highway leading from Baños to Riobamba. Constant accumulations of ashes occur on the steep western flank of the volcano as the wind almost always blows from the east. Combined with heavy rains they form devastating mudslides, destroying bridges and the road. Photo to the right shows a makeshift bridge. In the above picture an old lava flow can be observed in the exposed rock wall near Rio Verde, located some 20 km down the Pastaza valley. Vertical rock formation change drastically to horizontal one, representing the lava flow of an ancient big eruption of Tungurahua volcano.