@CWCB_DNR: March 2019 #Drought Update

From the Colorado Water Conservation Board/Colorado Division of Water Resources (Ben Wade):

In response to persistent and prolonged drought conditions throughout the southern half of the state and along the western border, ​the C​olorado Drought Mitigation and Response Plan​ was activated for the agricultural sector​ ​on May 2, 2018​, additional counties in northwest Colorado were added in September and activation remains in effect; information can be found HERE​.

February and March-to-date have both seen impressive snow accumulation statewide, but especially in the southern half of the state where snowpack is currently above 150 percent of normal for all basins. This persistent moisture and near normal temperatures has resulted in significant drought improvements across the region. We will continue to monitor throughout the snow melt season to determine inflows to reservoirs and streamflow levels. Post wildfire flooding remains a concern and will be closely monitored. The daily flood threat bulletin can be accessed May 1 through September 30 ​HERE​.

  • As of March 19th, exceptional drought (D4) and extreme drought (D3) have been entirely removed from Colorado. Severe drought covers just 0.63 percent of the state while moderate drought covers an additional six percent. Forty percent of the state is currently experiencing abnormally dry conditions, a significant improvement in recent weeks. Most of the western slope has seen three and even four class improvements in drought conditions since the start of the water year (see image below).
  • El Niño conditions are now present, and will likely continue through spring (80 percent chance) and even summer (60 percent chance) of this year. Historically spring during an El Niño event trends toward wetter conditions, and the NOAA Climate Prediction Center outlooks for April, and for the April-May-June period show increased chances of wetter-than-average conditions, with less confidence in the temperature outlook.
  • SNOTEL snow water equivalent statewide is 142 percent of average with all basins well above average. The highest snowpack is in the Southwest basins of the San Miguel, Dolores, Animas & San Juan at 158 percent of median, while the lowest is tied with both the Yampa-White and the North Platte at 128 percent of median (see image below).
  • Many basins, as well as the state as a whole are near maximum observed snowpack for this time of year and short term forecasts indicate that an active storm pattern is likely to remain.
  • Reservoir storage, statewide remains at 83 percent of normal but is expected to increase as soon as the runoff season begins. The South Platte, Colorado, and Yampa-White, all above 90 percent of average as of March 1st. Storage in the Arkansas and Upper Rio Grande basins are at 87 and 78 percent of normal, respectively. The Southwest basins of the San Miguel, Dolores, Animas & San Juan, and Gunnison remain the lowest in the state at 58 and 63 percent of normal, respectively.
  • Streamflow forecasts are near to above normal statewide and have been steadily increasing in recent weeks. As a result the Colorado Basin River Forecast Center has adjusted their April-July unregulated inflow forecasts as follows: Blue Mesa Reservoir 960 KAF (142% of average) a 32 percent of average increase, McPhee Reservoir 480 KAF (163% of average) a 51 percent of average increase. The Lake Powell inflow forecast is 9.50 MAF (133% of average) an increase of 2.2 million acre-feet or 31% of average.
  • The ​Drought Visualization Tool​ is now live; please take a minute to provide feedback on this tool ​HERE​.
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