Record-low snowpack likely to affect summer water supply
After measuring the amount of snow piled on Mount Hood and the water it holds, hydrologists with the Natural Resources Conservation Service are worried about what the lack of snowmelt will mean for this summer.
On Thursday, April 9, hydrologists Julie Koeberle and Amy Burke hiked about a quarter-mile into the Timberline ski area to the USDA Natural Resources Conservation Services Mount Hood snow telemetry, or SNOTEL, site, to manually sample the snowpack depth.
The trip was part of the NRCSs peak season snow survey.
Koeberle said peak season normally occurs around May 7, but with record lows of snowpack and warm temperatures, the area is peaking much earlier.
Usually the manual measurement process takes several people to drive the snow tube into the layers of snow and balance it on the scale. This year, there were only two hydrologists conducting the survey.
While Koeberle and Burke took measurements and remarked on the low amounts of snow, large quantities of snow fell from surrounding trees as it melted, banging off the metal roof of a site outbuilding.
Thats the sound of the ripe (snow), Burke said to Koeberle with an exasperated look.
After the two took three measurements from three parallel sites near the SNOTEL snow pillow and towers, they declared the 3.5 feet of snowpack contained 17 inches of water content 28 percent of normal.
Koeberle said during a normal year the NRCS Snow Survey Team measures 12 feet of snowpack with 60 inches of water content. Last year, there was 10 feet of snowpack.
At the beginning of April, 76 percent of Oregons long-term snow monitoring sites were measuring record-low snowpack. More than half of all snowpack measurements across the state recorded bare ground on April 1.
The last record-low year was 2005, Koeberle said. But this is lower than that.
While Bull Run and many other reservoirs get their water from spring rainfall, which is usually trustworthy in the Western Cascades, low snowpack will lead to reduced water supplies in the summer.
We have reached a point in the winter season where there is no doubt that the majority of streams and rivers in Oregon will have below-normal flows this year, due to lack of snow accumulations, said Scott Oviatt, NRCS snow survey supervisor. Overall precipitation since Oct. 1 has been near normal statewide.
However, warm temperatures result in the majority of precipitation falling as rain instead of snow.
Snowmelt runoff will not be available to help sustain mid and late summer stream flows, Oviatt said.
Oregon Gov. Kate Brown has declared drought in five Oregon counties Crook, Harney, Klamath, Lake and Malheur.
In Multnomah, Clackamas and Hood River counties, where the drought level is moderate, people who do not have access to rain-fed reservoirs and depend on stream flow for irrigation will be the most affected by record-low snow.
If we continue to get wet and cool conditions like weve seen in early April, that will help preserve the snowpack, Koeberle said.
However, if the rest of the spring brings warm and dry weather, NRCS encourages farmers, ranchers and forest landowners to consider conservation practices to improve their lands productivity during drought.
With the NRCSs SNOTEL site sending hourly measurements of Mount Hoods snowpack, along with other data gathered manually for the site, Koeberle and Burke had an idea of what they were walking into Thursday. But that didnt stop them from expressing distress as they surveyed the melting snow and bare spots.
To really see it, measure it and feel the snow in my hands ... its not good, Koeberle observed. Its surprising.
The NRCS hydrologists are also worried about a possible early season for forest fires and the impact on animals that rely on stream flow during the summer.
Humans are (mostly) OK, Burke says, but there are a lot of ecological impacts of no snow.
Roughly once a decade, most recently in 2005, there is a year with notably low snow levels. If that trend continues, next winter should see an uptick in snow.
Koeberle is optimistic about a healthy snowpack returning next year.
Were hoping this isnt a new trend, she said. But well just have to wait and see what happens.