Energy budget increases reduce mean streamflow more than snow-rain transitions: Using integrated modeling to isolate climate change impacts on Rocky Mountain hydrology

Lauren M Foster, Lindsay A Bearup, Noah P Molotch, Paul Brooks, Reed M Maxwell

Research output: Contribution to journalArticle

16 Scopus citations


In snow-dominated mountain regions, a warming climate is expected to alter two drivers of hydrology: (1) decrease the fraction of precipitation falling as snow; and (2) increase surface energy available to drive evapotranspiration. This study uses a novel integrated modeling approach to explicitly separate energy budget increases via warming from precipitation phase transitions from snow to rain in two mountain headwaters transects of the central Rocky Mountains. Both phase transitions and energy increases had significant, though unique, impacts on semi-arid mountain hydrology in our simulations. A complete shift in precipitation from snow to rain reduced streamflow between 11% and 18%, while 4°C of uniform warming reduced streamflow between 19% and 23%, suggesting that changes in energy-driven evaporative loss, between 27% and 29% for these uniform warming scenarios, may be the dominant driver of annual mean streamflow in a warming climate. Phase changes induced a flashier system, making water availability more susceptible to precipitation variability and eliminating the runoff signature characteristic of snowmelt-dominated systems. The impact of a phase change on mean streamflow was reduced as aridity increased from west to east of the continental divide.

Original languageEnglish (US)
Article number044015
JournalEnvironmental Research Letters
Issue number4
Publication statusPublished - Apr 13 2016
Externally publishedYes



  • climate change
  • energy budget
  • hydrology
  • integrated modeling
  • precipitation phase
  • Rocky Mountains
  • snow to rain transitions

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Environmental Science(all)
  • Public Health, Environmental and Occupational Health

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