Ice in Volcanic Clouds: When and Where

by William I Rose (featured speaker), Gregg JS Bluth, and I Matthew Watson
Michigan Technological University

ABSTRACT
Volcanic clouds are suspensions of particles, analogous to meteorological clouds. In volcanic clouds the particles include volcanic ash, hydrometeors (raindrops, snow, hail, graupel, sleet, etc), sulfate aerosols and particles that are mixtures or conglomerations of all the other particle types present. Ash fall is analogous to rain, hail or snow, and consists of large ash particles in descent. Ash fall occurs most markedly from the high energy first stage of volcanic clouds, with or without precipitation, near the vent and soon (<1hr) after eruption (Rose et al, 2000). Volcanic clouds exhibit a second stage of evolution, lasting a day or so, where rapid physical and chemical changes occur and when ash fall occur and when ash fall (and precipitation) is muted and controlled by aggregation of ash particles too small to fall by themselves. A third stage of volcanic clouds lasts several more days and consists of drifting over hundreds or thousands of km and very slow
fallout (Rose et al, 2003). Extended abstract (546 kB PDF).

OTHER ACTIVITIES
Dr. Rose is also interested in speaking with students about a new Peace Corps program in Natural Hazards. Details (47 kB PDF). Keep your calendar clear for a possible group lunch on Thursday or Friday. Details will be posted as they become available.