Auxiliary Material for

Snowpack Regimes of the Western United States

By

Ernesto Trujillo1, 2 and Noah P. Molotch3, 2, 4

1. Laboratory of Cryospheric Sciences, School of Architecture, Civil and Environmental Engineering, ÉcolePolytechniqueFédérale de Lausanne, Lausanne, Switzerland

2. Institute of Arctic and Alpine Research, University of Colorado, Boulder, CO 80309-0450, USA

3. Department of Geography, University of Colorado, Boulder, CO 80309-0450, USA

4. Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109-8099

Water Resources Research, 2014

Introduction

The auxiliary materials include 10 supplementary Figures to support the main article and analyses. The list of the supplementary Figures and their corresponding captions is:

1. fs01.tiff- Figure S 1. Sample daily SWE curve for a location with an intermittent snow cover for the period WY 2005-2007.

2. fs02.tiff- Figure S 2. Location of the four ecoregions in the Maritime regime (top panel) and scatter plots of the yearly pairs of the length of the snow accumulation season versus peak SWE (bottom panels) for the entire Western U.S. (black dots) and for each of the Maritime ecoregions (red dots). The plots display a total of 18498 year-pairs (black circles), with 1118 year-pairs in the North Cascades, 949 in the Cascades, 255 in the Klamath Mountains and 2236 in the Sierra Nevada.

3. fs03.tiff- Figure S 3. Location of the three ecoregions in the Continental regime (top panel) and scatter plots of the yearly pairs of the length of the snow accumulation season versus peak SWE (bottom panels) for the entire Western U.S. (black dots) and for each of the Continental ecoregions (red dots). The plots display a total of 18498 year-pairs (black circles), with 3777 year-pairs in the Middle Rockies, 2112 in the Wasatch and Uinta Mountains, and 2957 in the Southern Rockies.

4. fs04.tiff- Figure S 4. Location of the seven ecoregions in the Intermountain regime (top panel) and scatter plots of the yearly pairs of the length of the snow accumulation season versus peak SWE (bottom panels) for the entire Western U.S. (black dots) and for each of the Intermountain ecoregions (red dots). The plots display a total of 18498 year-pairs (black circles), with 234 year-pairs in the Eastern Cascades, 837 in the Blue Mountains, 675 in the Northern Basin and Range, 422 in Central Basin and Range, 709 in the Columbia Mountains/Northern Rockies, 1067 in the Idaho Batholith, and 492 in the Canadian Rockies.

5. fs05.tiff- Figure S 5. (a) Scatter plots of the yearly pairs of the length of the snow accumulation season versus peak SWE for the entire Western U.S. (Black circles), and year-pairs of the Arizona/New Mexico region highlighted in red. (b) Scatter plot of the yearly pairs of the ablation slopes versus the day of Water Year of peak SWE (DOWY of peak) for the entire Western U.S. (Black circles),, and the year-pairs of the Arizona/New Mexico region highlighted in red.

6. fs06.tiff- Figure S 6. Location of the four ecoregions in the Maritime regime (top panel) and scatter plots of the yearly pairs of the ablation slopes versus the day of Water Year of peak SWE (DOWY of peak) (bottom panels) for the entire Western U.S. (black dots) and for each of the Maritime ecoregions (red dots). The plots display a total of 18659 year-pairs (black circles), with 1118 year-pairs in the North Cascades, 951 in the Cascades, 267 in the Klamath Mountains and 2362 in the Sierra Nevada.

7. fs07.tiff- Figure S 7Location of the three ecoregions in the Continental regime (top panel) and scatter plots of the yearly pairs of the ablation slopes versus the day of Water Year of peak SWE (DOWY of peak) (bottom panels) for the entire Western U.S. (black dots) and for each of the Continental ecoregions (red dots). The plots display a total of 18659 year-pairs (black circles), with 3785 year-pairs in the Middle Rockies, 2115 in the Wasatch and Uinta Mountains, and 2964 in the Southern Rockies.

8. fs08.tiff- Figure S 8Location of the seven ecoregions in the Intermountain regime (top panel) and scatter plots of the yearly pairs of the ablation slopes versus the day of Water Year of peak SWE (DOWY of peak) (bottom panels) for the entire Western U.S. (black dots) and for each of the Intermountain ecoregions (red dots). The plots display a total of 18659 year-pairs (black circles), with 238 year-pairs in the Eastern Cascades, 836 in the Blue Mountains, 674 in the Northern Basin and Range, 422 in Central Basin and Range, 708 in the Columbia Mountains/Northern Rockies, 1067 in the Idaho Batholith, and 494 in the Canadian Rockies.

9. fs09.tiff- Figure S 9. Vertical distribution of snow pillow stations within each of the regions and regimes. Latitude (Lat.) ranges in decimal degrees are shown next to the legends.

10. fs10.tiff- Figure S 10. Start of the accumulation season at snow pillow stations in the Northern Cascades and Sierra Nevada regions between 1981-2008.