B. Lynn Ingram is Professor of Earth and Planetary Science and Geography at the University of California, Berkeley and co-author of "The West Without Water: What Past Floods, Droughts, and other Climatic Clues Tell Us About Tomorrow." She'll join us for Tuesday's AU to answer such questions as: What is "normal" climate in the West and how do we know what's normal? What do we learn from megafloods and megadroughts during the past 2,000 years, including most disastrous flood in the history of California and the West, which occurred in 1861-62? Why is climate so variable in the West? What does the past tell us about tomorrow?