Science News
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Precipitation declines in Pacific Northwest mountains

Date:
December 3, 2013
Source:
USDA Forest Service - Rocky Mountain Research Station
Summary:
Scientists previously attributed streamflow declines in the Pacific Northwest USA to warming temperatures based on data collected from long-term monitoring stations located in lower elevation valleys. In this new study, scientists monitored and observed declines in precipitation resulting from decreases in westerly winds in the mountains where the elevation is much higher concluding this may compound the changes in streamflow. This finding is significant since mountains are a primary water source for this region.
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FULL STORY

Recent Forest Service studies on high-elevation climate trends in the Pacific Northwest United States show that streamflow declines tie directly to decreases and changes in winter winds that bring precipitation across the region. Scientists believe the driving factors behind this finding relates to natural climate variations and man-made climate change.

Research Hydrologist Charlie Luce, with the Rocky Mountain Research Station's Aquatic Sciences Laboratory in Boise, Idaho, along with cooperators at the University of Idaho and the US Forest Service Northern Region, reflect on the decline of precipitation in the region's mountains for 60 years. Increasing wildfire area and earlier and lower streamflows have generally been attributed to warming temperatures.

"Our research," says Luce, "suggests that an alternative mechanism -- decreases in winter winds leading to decreased precipitation -- may compound the changes expected from warming alone. This is important because mountains are a primary water source for the region. Less precipitation leads to reduced runoff for communities, industry and agriculture. Decreased precipitation also exacerbates early snowmelt tied to warming temperatures. Acknowledging the effects of decreasing precipitation requires changes in how resource specialists approach climate change adaptation for water resources and forest management compared to preparing for increased temperature alone," he said. According to Luce, this may present important implications for changes in mountain precipitation and future water availability for other areas as well.


Story Source:

The above post is reprinted from materials provided by USDA Forest Service - Rocky Mountain Research Station. Note: Materials may be edited for content and length.


Journal Reference:

  1. C. H. Luce, J. T. Abatzoglou, Z. A. Holden. The Missing Mountain Water: Slower Westerlies Decrease Orographic Enhancement in the Pacific Northwest USA. Science, 2013; DOI: 10.1126/science.1242335

Cite This Page:

USDA Forest Service - Rocky Mountain Research Station. "Precipitation declines in Pacific Northwest mountains." ScienceDaily. ScienceDaily, 3 December 2013. <www.sciencedaily.com/releases/2013/12/131203110357.htm>.
USDA Forest Service - Rocky Mountain Research Station. (2013, December 3). Precipitation declines in Pacific Northwest mountains. ScienceDaily. Retrieved June 30, 2015 from www.sciencedaily.com/releases/2013/12/131203110357.htm
USDA Forest Service - Rocky Mountain Research Station. "Precipitation declines in Pacific Northwest mountains." ScienceDaily. www.sciencedaily.com/releases/2013/12/131203110357.htm (accessed June 30, 2015).

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