Drought Conditions Improving for Southeast Region

Update from Colorado Water Conservation Bureau

A cool and wet May has eliminated drought conditions across much of Colorado. With 31 weather stations recording the wettest month ever, statewide May 2015 was the wettest May since record keeping began in 1895. In total much of the state experienced 300% of normal May precipitation. June temperatures to-date have been slightly warmer than average and the short term forecast shows decreased likelihood of precipitation. Water providers are reporting full systems and below average demand compared to this time last year.  

Water year-to-date precipitation at mountain SNOTEL sites, as of June 16, is at 97% of normal, an 11% improvement compared to the last drought update, due to record breaking May precipitation.  

In the San Miguel, Dolores, Animas and San Juan river basins June precipitation to-date is 350% of normal, and has already exceeded average total June precipitation. Coupled with abundant May accumulation this region has received roughly 10 inches of precipitation since the beginning of May, leading to drought elimination in this area of the state.  

Below tree-line, most basins have very little snow remaining at this time of year, although the cool and wet conditions over the last month have helped to slow melt off.  

Cooler than average temperatures in May also contributed to greatly improved drought conditions, with most sites reporting below average evapotranspiration and some reporting record low evapotranspiration.  

Reservoir Storage statewide is at 107% of average as of May 1st. Storage in the northern half of the state is above average with multiple basins near 110% of average. The Colorado River basin is experiencing its highest storage levels since the turn of the century. The Upper Rio Grande and the basins of Southwestern Colorado currently have the lowest storage at 66% and 89% of average, respectively. Both have seen below average storage levels for multiple years.  

The Surface Water Supply Index (SWSI) is abundant in all of the South Platte, and near normal is the Colorado River, Gunnison, and Arkansas, but showing spots of moderate to severe drought in the Upper Yampa, Conejos and the Piedra. The vast majority of the state has seen improvements in the SWSI since last month. 

El Niño has continued to gain strength over the last few months and is poised to become a strong event, if not a “Super El Niño.” The last “Super El Niño” was in 1997 when Colorado experienced above average precipitation.  

All long term forecasting tools indicate normal to above normal precipitation in the coming months, with some indication that the monsoon season may come early.  

The US Drought Monitor illustrates current drought conditions across Colorado. Drought conditions have greatly improved compared to last month. With only a small portion of the state experiencing D0 or abnormally dry conditions. This is the first time since September of 2010 that the state does not have any D1-D4 drought classifications. 

May precipitation ranged from a high of 345% of average in the San Miguel, Dolores, Animas and San Juan river basins to a relative low of 197% of average in the Yampa/ White basin. May precipitation greatly eclipsed accumulation from all other months this water year, in all basins, with a statewide average in excess of 300% of normal. 

Based on historical analog years, this year’s summer is favored to remain near-normal or even wetter than normal, while the upcoming fall leans towards wet for our state.