How Volcanoes Work

 Image Described in Caption
 Lahar at Mt. Pinatubo (1991) -- The 1991 Mt. Pinatubo generated voluminous lahars, most of which were cold as the result of the arrival of a major hurricane at the time of the eruption. Approximately 700 deaths were attributed to these lahars. The photo shown here demonstrates a relatively small-volume, valley-filling lahar associated with this event. Courtesy of NOAA.