November 2013 Drought Update from Colorado Water Conservation Board

Continued precipitation across much of the state has led to significant improvements in most of Colorado. However the Arkansas basin is still experiencing exceptional, D4, drought conditions. Storage levels are strong and better than they were this time last year, easing concerns of municipal providers. Early season snow has been decent, but long range forecasts paint an unclear picture as to what we can expect throughout the winter months. Consequently, activation of the state drought plan remains in effect.  

Strong and persistent fall rains coupled with a good start to the snow accumulation season has resulted in large improvements to the US Drought Monitor for Colorado. Currently, 74% of the state is in some level of classification on the US drought monitor. However 53% of that is characterized as “abnormally dry” while an additional 9% is experiencing D1 or moderate drought conditions. Only 8% is classified as severe, 2.5% as extreme and only 1.47% of the state remains in exceptional drought. In comparison, three months ago 25% of the state was experiencing extreme and exceptional (D3 and D4) drought, while at the start of the calendar year 53% was classified as D3 or D4.  

A cool October followed by a warm start to November has resulted in water year to-date (water year 2014 began Oct 1, 2013 and will run through September 2014) temperatures that are slightly below normal. The latest Climate Prediction Center forecast shows the probability for warmer temperatures through December across much of the state.  

September and October precipitation were both well above average statewide. Currently, water year to-date precipitation is 107% of average with the northern part of the state near average to above average (99-140%) and the basins of the southwest, Rio Grande and Arkansas ranging from 83-88%.  

Reservoir storage as of November 1st has rebounded to 83% of average statewide. Many providers were able to store substantial amounts of water during the September rain events. Denver Water, the state’s largest water provider, was able to store water in September for the first time in their history. Consequently, areas of the state that have received the most beneficial precipitation are also showing the higher reservoir storage levels. The Yampa/ White remains the highest storage levels in the state at 112% of average; while the South Platte and the Upper Colorado are reporting storage levels of 107 and 91% respectively. The southern portion of the state has lower storage levels at 72, 68 and 67% of average in the Arkansas, Gunnison and Southwest basins respectively. The Rio Grande continues to have the lowest storage levels in the state at 47% of average.  

The Climate Prediction Center seasonal drought outlook released November 21, 2013 and valid for November 21- February 28, 2014 illustrates persistent drought across southeastern Colorado and the eastern plains along the Kansas and Nebraska boarder. Temperature forecasts for the same period show an equal chance of being above and below average.  

ENSO conditions remain neutral, which offers less guidance for long range climate outlooks. However, early season snow in the mountains is consistent with the snowpack forecast for January 1st that is near or above average in all basins. The statistical precipitation forecast for January- March 2014 shows dryness across much of the state, but has had limited operational skill since 2000.  

The US Drought Monitor illustrates current drought conditions across Colorado. Significant improvements have been made over the last few months as precipitation has increased in many areas of the state. Currently the majority of the state is experiencing abnormally dry conditions while 21%, isolated to the eastern plains, is classified as experiencing moderate through exceptional drought conditions. 

Fall snowpack as of November 20th is above average at 124% statewide. The northern basins are faring the best with the Yampa/White and North Platte at 160 and 141% of average respectively. All others are above average ranging from 100% in the Arkansas to 124% in the Colorado. 

Statewide reservoir storage ranges widely from 47% of average in the Rio Grande to 112% in the Yampa/White. As a whole the state storage levels sit at 83% of average, a 10% increase from September 1st.