Measuring volcanic ash on snow
Ashfall deposit in Anchor Point, AK from the April 4, 2009 eruption of Redoubt Volcano. This is an example of a well-documented photograph of ashfall by a citizen scientist. The scale is from AVO's Ash Collection Worksheet downloadable from: http://www.avo.alaska.edu/ashfall.php
Image courtesy of the photographer, Lori Blank. AVO has permission to use this photo.