Snowpack news: Every basin is below 50% of the three-year average, what was there is running off early this water year




Whoa Nellie! Snowpack is a thing of the past. Click on the thumbnail graphics to the right for the statewide map and the statewide Basin High/Low graph along with the hydrograph for Clear Creek at Golden.

Clear Creek was running 10 CFS higher than median yesterday.

Meanwhile, here’s the executive summary from last week’s Water Availability Task Force from the Colorado Water Conservation Board. Here’s an excerpt:

March 2012 tied 1966 for the driest on record and it was the third warmest March for Colorado. Records date back to 1895. April has seen some improvement in precipitation with beneficial precipitation on the eastern plains that has lessened extreme and severe drought conditions. However, much of Colorado remains well above average for temperature and below average for precipitation. All major basins of the state have seen significant declines in snowpack. All continue to be below normal for the year. Statewide snow water equivalent at SNOTEL sites is 39%. Severe drought conditions have been reintroduced in the San Luis Valley and established throughout portions of the Yampa/White, Colorado and Gunnison River basins. Water providers are watching the situation very closely.

 To date, April temperatures have been 2-8 degrees above average for most of Colorado, with multiple areas experiencing temperatures 10 degrees above normal.

 Historically, Colorado reaches its average peak snow water equivalent for the season by April 12. However, this year only 68% of average was achieved and that peak occurred a full month early on March 12, 2012. Some basins, including the South Platte and the San Miguel/ Dolores/ Animas/ San Juan peaked as early as March 4.

 Reservoir storage remains above average in the Yampa/White, Gunnison, Colorado, South Platte Basins, and San Miguel/ Dolores/ Animas/ San Juan. Statewide, reservoir storage is 108% of average. The Rio Grande and the Arkansas River basins continue to be the regions with the lowest reservoir storage levels in the state, at 73% and 86% of average, respectively.

 As of the April 17 US Drought Monitor, 95% of Colorado is experiencing some level of drought classification, down from 100% two weeks earlier. D1, moderate drought, conditions remain in much of the Arkansas River basin and the northern and central mountains, while D2, severe drought conditions, have been introduced in the northwestern part of the state and the Rio Grande River basins. D0, abnormally dry conditions, account for the rest of the impacted areas of the state (35%). Removal of D0 on the central plains and a reduction of D2 in the southeastern plains resulted from early April storms that brought substantial precipitation.

 The Surface Water Supply Index (SWSI) values range from -3.86 in the Arkansas headwaters sub-basin to -0.13 in the Upper Arkansas sub-basin. The Arkansas headwaters’ low value is, in part, due to operational drawdown of Homestake Reservoir. All SWSI values throughout the state are negative.

 La Niña conditions have weakened, and the long term forecast for late spring (April-June) shows a shift towards dryness covering southwest Colorado, near-normal moisture over the eastern plains, and a slight shift towards wetness in northwest Colorado.

 There is about a 40% chance that we could see a transition towards El Niño within the next few months, which would favor more moisture for the state.

 On the West Slope, combinations of prevalent fine fuels and the possibility of a drier than normal season could lead to significant fire potential concerns as the season progresses.

More CWCB coverage here.

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