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WATER LINES: Time to start watching snowpack figures again

Hannah Holm
WATER LINES
Free Press Weekly Columnist
Picture taken Oct. 27 of the Gunnison River where Blue Mesa Reservoir usually is. The photographer was standing on Hwy. 149 just south of the bridge from US Hwy 50, looking west across what is normally the upper end of the lake.
Hannah Holm |

A damp, cool morning in Grand Junction and winter storm warnings for the mountains put me in the mood to look up climate data and forecasts for the 2014 water year, which started Oct. 1, 2013.

For the first time in months, I’m looking at SNOTEL figures! SNOTEL is short for snow telemetry. The Natural Resource Conservation Service maintains a network of SNOTEL sites across the western U.S. in order to develop water supply forecasts, and you can access their data via the web.

Snowpack figures can look pretty dramatic this time of year, due to the large year-to-year variability in when the snow starts to pile up and the fact that a mere 2 inches on top of 1 inch increases it by 200% — while the same 2 inches later on may barely make any difference, percentage-wise.



So far this year, we’re getting off to a good start. On Oct. 29, all of western Colorado’s river basins registered at least 128% of the historical median amount of water held in the form of snow for that date. Underscoring the need to not take snowpack numbers too seriously at this time of year, however, is the fact that the same set of figures showed one river basin in southern Utah at over 2000% of the median for this date! Just one week before, the same basin showed no data.

As the water year wears on, the snow numbers will get less dramatic and start to tell us more about what to expect when next spring’s runoff begins. For now, you can learn more by looking at current hydrologic conditions and long-range weather forecasts.



October so far has been a good one for precipitation in the Upper Colorado River Basin. The only areas receiving significantly less than average are in southeastern Utah, but even that area received good moisture in September. These precipitation numbers are reflected in soil and vegetation moisture levels, which are normal-to-wet across most of the Upper Colorado River Basin.

Streamflows are not quite as good, with the Colorado River at 93% of normal near the Colorado-Utah state line, the Green River at 75% of normal at Green River, and the San Juan River near Bluff at 41% of normal for this time of year.

Reservoir levels continue to show the drought conditions the region experienced in 2012 and the first part of 2013. Blue Mesa Reservoir, Colorado’s largest, is 42% full; Lake Powell, the Upper Basin’s largest is 45% full, while Navajo and Flaming Gorge are doing a bit better at 56% full and 75% full, respectively. Reservoir levels in eastern Utah are significantly lower.

With reservoir levels like that, it will be really helpful if the snowpack continues on its positive trajectory. The National Weather Service Climate Prediction Center long-range forecasts aren’t sending much of a signal regarding whether that’s likely to happen or not, though. Its forecast shows equal chances of wet, dry or normal conditions through this fall and early winter.

Klaus Wolter, a NOAA meteorologist based at the University of Colorado, has issued an experimental forecast showing above-average snowpack for most Colorado river basins on Jan. 1; but given that most of the region’s snow typically accumulates later on, even that doesn’t tell us much about what kind of water year to expect in 2014.

Given that the professional prognosticators seem to be having trouble reading the tea leaves, we might as well monitor snowpack numbers after all. At least they can tell us something about skiing conditions and, little-by-little, fill in the picture on next year’s water supply.

Two good websites for tracking a wide range of climate data are:

The National Integrated Drought Information System’s Upper Colorado Regional Drought Early Warning system, hosted by the Colorado Climate Center at http://climate.colostate.edu/~drought/

The Intermountain West Climate Dashboard maintained by Western Water Assessment at the University of Colorado http://wwa.colorado.edu/climate/dashboard.html.

Water Lines is a series of articles coordinated by the Water Center at Colorado Mesa University in cooperation with the Colorado and Gunnison Basin Roundtables to raise awareness about water needs, uses and policies in our region. To learn more about the basin roundtables and statewide water planning, and to let the roundtables know what you think, go to http://www.coloradomesa.edu/WaterCenter. Hannah Holm is coordinator of the Water Center at Colorado Mesa University.


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