1. U.S. Geological Survey (USGS), Northern Rocky Mountain Science Center, 2327 University Way, Suite 2, Bozeman, MT 59715, USA.
2. School of Natural Resources, University of Arizona, 325 Biosciences East, Tucson, AZ 85721, USA.
3. Laboratory of Tree-Ring Research, University of Arizona, 105 West Stadium, Tucson, AZ 85721, USA.
4. Department of Civil and Architectural Engineering, University of Wyoming, Laramie, WY 82071, USA.
5. School of Geography and Development, 412 Harvill Building, University of Arizona, Tucson, AZ 85721–0076, USA.
6. USGS, National Research Program, Water Resources Division, Tucson, AZ 85719, USA.
7. Climate Impacts Group, University of Washington, Post Office Box 355672, Seattle, WA 98195–5672, USA.
8. Department of Geography, University of Western Ontario, London, Ontario N6A 5C2, Canada.
9. College of the Environment, University of Washington, Post Office Box 355679, Seattle, WA 98195–5679, USA.