Hello Forrest - I forwarded your question to Dave Schneider, our remote sensing specialist, and he said this trajectory was possible. At that time, he intended to post a discussion about it in the Yahoo volcanic clouds group, but we have been pretty busy with both Pavlof and Shishaldin. If he sends me a copy of his post, I'll forward it to you. Thanks, Cheryl -------- Forrest M. Mims III wrote: On the evenings of 18 and 19 November my twilight photometers in South Central Texas (Seguin) detected an unusually thick aerosol layer from 10-30km. This layer is much thicker than the usual stratospheric aerosol layer at an elevation of about 20 km. Also, on both evenings the twilight glow was significantly enhanced. Can you please advise me if any of your forward trajectories suggest aerosols from Pavlov and/or other sources might have reached my site? Thanks very much. Forrest Mims (www.forrestmims.org)(This inquiry may be forwarded and/or posted.) -- Cheryl Cameron Geologist, Alaska Volcano Observatory Alaska Division of Geological & Geophysical Surveys voice: 907-451-5012 fax: 907-451-5050