Drought/snowpack/runoff news: ‘Early snowmelt leads to early runoff timing’ — Mage Skordahl (NRCS)


Direct irrigators are likely caught in a double whammy for the summer. The runoff came off early before they needed the water, and the calls on the streams will likely be very senior for the summer, leaving many short when it’s time to finish off the their crops. Click on the thumbnail graphic for the table that accompanied the release. Here’s the June news release from the Natural Resources Conservation Service (Mage Skordahl):

Weather patterns that began in March and April continued throughout the month of May; warm temperatures and below average precipitation persisted at SNOTEL sites across the state during the month. Phyllis Ann Philipps, State Conservationist with the Natural Resources Conservation Service (NRCS) stated, “Recent data confirms that the statewide snowpack reached maximum accumulation on March 7, 35 days ahead of the average peak date and that it has disappeared approximately a month early as well.” The June 1 snowpack report shows that the statewide percentage was just 2 percent of average with many basins reporting no measurable snow.

The latest data from SNOTEL sites in Colorado reveal that the snowpack across the state is almost completely melted out. As of June 6 the Gunnison, Colorado, Arkansas, Upper Rio Grande, and combined San Miguel, Dolores, Animas and San Juan river basins were all reporting no snow. The only SNOTEL site in the state with noteworthy snow remaining is the TOWER site in the Yampa river basin which is reporting 2.8 inches of SWE at just 7 percent of average. “The mountains just did not receive the spring storms needed to boost this season’s snowpack. Our SNOTEL sites recorded below average precipitation in March, April and May throughout the state “, said Philipps.

The timing of snowmelt runoff in most basins in Colorado has been about a month earlier than normal this year and streamflow volumes are forecast to be their lowest since 2002. For the remainder of the forecast season (June – July) it is expected that on average streams across the state will flow at around 30 percent of average. In some basins, such as the Yampa and White rivers, June to July forecasts are much lower with current forecasts ranging from 9 to 22 percent of average.

The best news for water availability in Colorado this spring and summer is within the statistics for reservoir storage. As of June 1, storage statewide had decreased from last month but was near average at 98 percent of average and 61 percent of capacity. The storage volumes in all the major basins remain above or near average except for in the Arkansas and Upper Rio Grande river basins where storage has dropped to 78 and 57 percent of average respectively. This stored water should provide some reprieve from potential shortages this summer statewide but water users in all basins and especially in the Arkansas and Upper Rio Grande should be prepared for late season shortages.

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