May 2018 Drought Update from CWCB

In order to respond to persistent and prolonged drought conditions throughout the southern half of the state and along the western border, the Governor activated the Colorado Drought Mitigation and Response Plan for the agricultural sector on May 2, 2018 , in the following counties: Montezuma, La Plata, Archuleta, Conejos, Costilla, Las Animas, Baca, Prowers, Bent, Otero, Huerfano, Alamosa, Rio Grande, Mineral, Hinsdale, San Juan, Dolores, San Miguel, Ouray, Montrose, Saguache, Custer, Pueblo, Crowley, Kiowa, Cheyenne, Lincoln, El Paso, Elbert, Gunnison, Mesa, Delta, Garfield and Rio Blanco.

All of these counties are experiencing severe, extreme or exceptional drought as classified by the US Drought Monitor, and many have already received some level of drought designation from USDA . If present trends continue, other regions and sectors of the state’s economy may also be affected. Those areas will continue to be monitored closely.

■ October 2017 through April 2018 was the 5th warmest and the 5th driest on record for the state as a whole. Some locations throughout southern CO have experienced their driest and/or warmest Oct-Apr period on record.

■ Most regions of Southern Colorado reached their snow accumulation peak two to three weeks early and have experienced rapid snowmelt, resulting in melt out occurring three weeks earlier than normal.

■ Streamflow forecasts in the southern half of the state are extremely low, with multiple sites showing below 15 percent of normal.

■ Demand is increasing and reservoir storage in the most heavily impacted areas, the Southwest basins of the San Miguel, Dolores, Animas & San Juan have seen significant decreases in reservoir storage over the last two months. This combined basin currently has 91 percent of normal storage, the lowest storage levels in the state.

■ Isolated cattle sell off and prevented planting of some acreage has been reported. Due to high hay prices we anticipate additional cattle sell off, and unless conditions improve additional prevented and failed crop acres are likely.

■ Windy, dry conditions fueled fires in April leading to numerous large wildfires on both the west slope and the eastern plains. Current forecasts indicate above average potential for large wildfires through June with late summer fire potential dependent on monsoon conditions.

■ As of May 15, exceptional drought, D4, continues to affect southwest Colorado and has also been introduced in the Sangre de Cristo Mountains, covering eight percent of the state. Extreme drought, D3, covers 23 percent of the state; severe drought 20 percent and 14 percent is classified as moderate drought. An additional 14 percent of the state is currently experiencing abnormally dry conditions.

■ Reservoir storage statewide is at 111 percent of normal, with all but the southwest basins above average. The Arkansas basin is reporting the highest average storage at 129 percent. Front Range water providers mainly draw water resources from areas of the state that received near normal winter precipitation, and are therefore expecting reservoirs to fill, and are not anticipating any water use restrictions outside normal operations.

■ The Surface Water Supply Index (SWSI) values have declined slightly May 1, with much of the western slope classified as extremely dry. These values are largely driven by below average streamflow forecasts. The sub-basin with the highest value includes Lake Granby, a large reservoir.

Colorado as a whole has been dry since the start of the water yar on October 1, 2017; however the southern half of the state has seen much drier conditions than the north. Many regions of the southern half of the state are experiencing record dry conditions with records dating back 123 years.

Southern Colorado has continued to see an expansion of exceptional drought conditions in May, with D4 now present in the southwest. Northeast Colorado has seen cool temperatures and near normal precipitation resulting in improved conditions.