November 15, 2022 #Colorado Water Availability Summary – Water Year 2022 — @CWCB_DNR #snowpack #ENSO

Colorado Drought Monitor map November 29, 2022.

Click the link to read the summary on the Colorado Water Conservation Board website (Ben Wade):

Observed temperature
Water year 2022 was the sixth warmest and 35th driest on record going back to 1896. At a national scale, Colorado was part of a southern and central plains drought over the Water Year 2022. The South Platte basin was much drier than normal, while parts of the state west of the continental divide experienced wetter conditions. 2022 was a “warm dry” year as compared to historical average temperatures and precipitation data. However, this temperature data was heavily impacted by a very mild early season period from October through November 2021. As in recent years, February 2022 was the coldest month of the year.

Observed precipitation and drought conditions
Precipitation for the 2022 water year started dry, then was impacted by about 15 days of strong moisture in late 2021. April was dry and also recorded as the windiest month on record. The state had a wet July and monsoonal moisture in the central and southern parts of the state was very impactful on overall precipitation trends. In the October/November timeframe the state experienced wetter conditions in the Northwestern/Western parts of the state, while it has remained very dry on eastern plains. The 30-Day Standardized precipitation Indices (SPI) shows dry conditions over the last month, but the longer term 24-month SPI indicates wetter than normal conditions throughout the central part of the state. Abnormally dry and moderate drought remains across much of the west slope. The Drought Monitor reflects few or no changes because changes move slowly this time of year, however drought doesn’t stop. Precipitation has been very low in Baca, Bent, and Prowers counties. Overall, the country is suffering from extensive drought, and Colorado is no exception.

Credit: Colorado Climate Center

Observed streamflows
Going into Water Year 2023 Colorado has some of the best antecedent soil moisture in years. This is good news but not the only variable that matters. Vegetative health shows decent conditions west of the divide, but on the eastern side of the divide conditions are a lot drier than normal. Precipitation is near normal at 95% of median WYD precipitation.

Westwide SNOTEL basin-filled map December 4, 2022 via the NRCS.

Snowpack and reservoir storage
Statewide snowpack is at 118% above median for this time of year, but that number is skewed a bit by higher than average low elevation snowpack for this time of year. Snowpack on the western slope is generally above average, while the eastern slope is generally below average. All basins are above average except South Platte and Laramie. Statewide reservoir storage is at 77% of normal. Releases from Blue Mesa are driving low reservoir storage in Gunnison Basin. There is a human element to low storage in Gunnison and Southwest basins due to water being sent downstream.

Seasonal outlook
La Niña looks likely to continue through early winter and possibly beyond. On average, the Northern Rockies are wetter
during La Niña and with colder temperatures that can result in good snowpack conditions . Drier conditions may impact the
southern part of the state.

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