@CWCB_DNR November 2020 #Drought Update

Click here to read the update (Megan Holcomb & Tracy Kosloff):

Water Year 2020 has concluded as the 12th warmest water year on record in Colorado since 1895. The winter months presented near normal temperatures with warmer temperatures occurring throughout summer months. Water Year 2020 was the third driest water year on record, trailing only 2002 (driest) and 2018 (2nd driest). October temperatures were above normal and precipitation was below average for the majority of the month, despite a strong cold snap that hit the state just before Halloween. So far in November, eastern Colorado has experienced above average temperatures that are likely to continue, while several decent storms blanketed the mountains, resulting in average snowpack for this time of year in western Colorado. On November 30th, Governor Polis activated Phase 3 of the State Drought Mitigation and Response Plan along with a Municipal Water Impact Task Force to help water providers coordinate and prepare for a potential multi‐year drought.

Colorado Drought Monitor November 24, 2020.

A critically hot spring, high winds, dry summer, and multiple monsoon seasons with poor to no moisture have contributed to 2020’s record breaking fires. The three largest wildfires in Colorado history occurred in the summer and fall of 2020. Historically, Colorado’s largest wildfires occur in June following poor winter snowpack and an early springtime melt out. However, the Cameron Peak and East Troublesome fires experienced rapid and intense expansion in October ‐ a completely unprecedented phenomenon.

The Nov. 25 U.S. Drought Monitor logged 27% of the state in D4 (exceptional) drought conditions; D3 (extreme) drought in 47% of the state; D2 (severe) covering 19%; and D1 (moderate) drought covering 6% of the state.

The 90‐day Standardized Precipitation Index (SPI) (August 19 to Nov 16) values continue to show drier than normal conditions across the state.

The ENSO forecast predicts that moderate La Niña conditions will last through the winter. La Niña generally means an increase in moisture to the north and less to the south. Historically this pattern leads to snowier winters in the northern Rockies and less precipitation to the south.

The NOAA Climate Prediction Center three month outlook maps indicate an increased chance for above average temperatures over the winter with an equal chance (e.g. unclear trend) of precipitation.

Statewide reservoir storage is currently at 82% of average. Storage in the northern half of the state is near average while the southern basins range

Municipal water providers continue to report increased demands and most municipalities report normal to slightly below normal storage. Water providers are closely monitoring conditions due to the likelihood of extended drought to prepare for a dry spring.

Leave a Reply