April 2015 Drought Update from CWCB

Colorado has been warm and dry for so far this spring. March was four degrees above average across much of the state making it the 6th warmest on record. In addition, the three week period from March 9- April 1, 2015 was one of the driest on record. As of April 14th, many river basins had zero percent of average precipitation for the month to date, while others had just seven percent. Conditions are widely expected to change as spring storms move through the state over the next week and deposit a good amount of moisture.

Water year-to-date precipitation at mountain SNOTEL sites, as of April 14, is at 57% of normal. Most basins have already passed their normal peak accumulations date and are experiencing melting. However, cooler conditions and snow are expected over the next two week and that will help to slow the rate of snowmelt.

April 1st streamflow forecasts have dropped significantly from the previous month. Statewide forecasts range from 37-102% of average. The highest forecast is 102% in the Colorado at the Dillon Reservoir inflow, while the lowest streamflow forecast is 37% of average in the Yampa basin on Elkhead Creek.

Reservoir Storage statewide is at 108% of average as of April 1st a slight improvement from last month. Storage in the northern half of the state is well above average with multiple basins seeing storage levels in excess of 120% of average. The Upper Rio Grande and the Arkansas have the lowest storage at 77% and 79% of average respectively. Strong storage is helping to alleviate concerns about dry conditions.

The Surface Water Supply Index (SWSI) is near normal in much of the South Platte, Gunnison and Arkansas, but showing moderate to severe drought in portions of the state. The lowest SWSI value in the state is in the North–Fork Gunnison where stream flow forecasts are currently 36% of average, the highest value is in the Upper Arkansas.

Current El Nino conditions have strengthened and are forecasted to continue strengthening, with some projections indicating a possible Super El Nino. El Nino typically favors more precipitation in Colorado during the growing season.

The wildfire season is forecast to be “normal” this year and the state is well positioned to respond. A normal fire season equates to roughly three thousand fires across the state.

Water providers in attendance reported their systems are in good shape, largely due to plentiful storage. While demand has begun to increase it remains near where it was at this time last year.

The US Drought Monitor illustrates current drought conditions across Colorado. Conditions on the western slope have declined since last month from D0 (abnormally dry) to D2 (severe drought). 23% of the state is experiencing D0 or abnormally dry conditions, while 12% is experiencing D1, moderate drought conditions. 40% of the state is currently classified as D2, severe drought conditions. 25% of the state remains drought free.

Statewide, reservoir storage, as of April 1st is 108% of average, up from 90% of average this time last year. The northern portion of the state and the Gunnison basin has above average storage; while the southern portion of the state is less robust. Strong storage conditions are helping to alleviate drought concerns of water providers across the state.

Precipitation statewide has been below normal every months of the water year thus far. The water year runs from October 1- September 30th. Conditions are being closely monitored, especially in southern portions of the state where dry conditions have been more persistent. Statewide, reservoir storage, as of April 1st is 108% of average, up from 90% of average this time last year. The northern portion of the state and the Gunnison basin have above average storage; while the southern portion of the state is less robust. Strong storage conditions are helping to alleviate drought concerns of water providers across the state.