#Drought news: The aridification of the #ColoradoRiver Basin #COriver

Click here to go to the US Drought Monitor website. Here’s an excerpt:

Summary

Early in the drought week, moderate precipitation fell in an area covering southern Minnesota stretching southeastward through central Iowa and Illinois, southern Indiana, Kentucky, southwestern Virginia, and much of North Carolina. Heavier precipitation fell in coastal California and the Sierra range. Coastal Oregon and Washington also saw moderate to heavy precipitation amounts during the first half of the drought week. The Northeast experienced its fourth Nor’easter in as many weeks. Near the end of the drought week, a swath of precipitation fell from Texas, eastern Oklahoma, into Missouri and Indiana. The dry pattern continued for the drought stricken areas of the southern Rockies and Plains and parts of the Southeast…

South

Precipitation was generally above normal (0.5-2.0 inch surpluses) across north central Texas, eastern Oklahoma and extreme northwestern Arkansas during the USDM period. During the last 30 days, much of Texas, Oklahoma and Louisiana were running 1-3 inches below normal while Arkansas was as much as 5 inches above normal. According to the USDA, 65 percent of wheat in Texas was in poor to very poor condition while 72 percent of topsoil moisture across the state was short to very short. Moderate and Extreme drought was expanded in central and parts of southern Texas. Precipitation continues to miss western Oklahoma where 28-day streamflows are running below the fifth percentile and precipitation for the last 6-months is around 20 percent of normal. Extreme drought was expanded to cover more of the Panhandle of Oklahoma, reaching into Kansas and Texas. Drought and dryness is not currently affecting the majority of the other states of the region…

High Plains

Precipitation was light across the region during the USDM period as, generally speaking, less than 1 inch of precipitation fell. Aside from Kansas and Colorado, precipitation during the past 30-days was just ahead of normal as surpluses of 0.50 to 1 inch fell in much of North Dakota, eastern South Dakota and eastern Nebraska. Winter wheat conditions were rated 49 percent poor to very poor in Kansas while 69 percent of topsoil moisture across the state was short to very short. In southern Kansas, 180-day precipitation departures are 4-8 inches below normal. In southwestern South Dakota, recent precipitation allowed for D0 and D1 to be contracted. Severe drought (D2) was contracted in west central Colorado and in the Dakotas. Extreme drought (D3) was expanded southern and western Colorado and southern Kansas…

West

Copious amounts of precipitation fell in the West during the USDM period, helping to restore the below-normal seasonal mountain snowpack in the Sierra. In the lower elevations, the atmospheric river event caused flash flooding and mudslides in the same area where forest fires last December charred the landscape. Little to no precipitation fell during the week in Arizona and New Mexico. Despite the recent precipitation in California, departures are evident beyond 30 days. At the 6-month time scale, precipitation amounts are 30-50 percent of normal in Southern California. However, for the same period (6-month), the recent storm brought the precipitation totals closer to normal in the central and northern Sierra. River basin snow water content now measures 75-90 percent of average in the central Sierra. The recent storm allowed the contraction of drought across much of the West this USDM period. However, where the precipitation did not fall (Desert Southwest and northwestern New Mexico), Severe and Extreme drought (D2-D3) was expanded.

*For details on Eastern Colorado and Eastern Wyoming, refer to the High Plains region…

Looking Ahead

During the next 5 days, precipitation amounts are forecast to be high (3-5 inches) in an area stretching from Louisiana, Arkansas, Alabama, western Tennessee and into Kentucky. Elsewhere, lighter precipitation is forecasted to fall in the northern and central Rockies, High Plains, and Northeast. The drought-stricken Four Corners region, western Texas and the Southwest are expected to continue to be dry.

The 6-10 day outlook from the Climate Prediction Center calls for an increased chance of below-normal precipitation in the High Plains stretching into the Great Lakes region while the highest probability of above normal temperatures is centered around the Southwest. The probability of above-normal precipitation is highest in the South. Below-normal precipitation is most likely to occur across parts of the Southwest.

From KUNC (Luke Runyon):

“Everybody talks about 2001 and 2002,” [Chuck] McAfee says. “That one was a very dry time just like this is. This is appearing to be scarier and worse.”

By most measures, portions of the American southwest in the Colorado River Basin are in their 18th year of drought. A handful of wet years dot the historical record in that stretch of time, but storms haven’t brought enough moisture to fill reservoirs and replenish groundwater. It’s the longest period of sustained dry and warm weather since consistent records have been kept.

That’s leading some to ask: If a drought lasts that long, is it still a drought or something else entirely?

[…]

The lack of robust conversations about the dry conditions might be a symptom of our limited vocabulary to describe what’s going on, says Brad Udall, a climate and water researcher with Colorado State University.

“Language is how you think, right? It’s how your opinions form and how your thought processes work. If you have the wrong words in your thoughts, you might actually come up with the wrong solutions,” Udall says.

Udall and other academics with the Colorado River Research Group published a paper arguing that our conversations about drought in the southwest need to change — specifically the word “drought.” It’s no longer a helpful concept in talking about the fundamental climate shifts reshaping the southwest, Udall says.

“Drought is often viewed as a lack of water and is viewed as a temporary situation,” Udall says.

But the latest science points toward a drier, warmer future for the Colorado River Basin, Udall says. If we see that change as “drought,” as something that eventually goes away, we hold onto false hope and fail to adequately prepare…

“This isn’t really drought,” [Udall] says. “This is the ongoing aridification of the Colorado River Basin and we think we should start to talk about it in these terms rather than this older term, ‘drought.’”

Here’s the March 2018 Drought Update from the Colorado Water Conservation Board (Taryn Finnessey) and Colorado Division of Water Resources (Tracy Kosloff):

Despite near normal precipitation across most of the state in February, March precipitation has been well below average statewide. Currently Colorado is experiencing the 3rd lowest snowpack on record, with only 2002 and 1981 being drier. Extreme drought has expanded to cover most of Southwestern Colorado, The San Luis Valley and Southeastern Colorado. West Slope providers with limited storage are concerned about the demand season and thinking about possible restrictions, while Front Range providers are thinking about conservation messaging.

  • As of March 23rd, statewide snowpack at SNOTEL sites is 69 percent of average. The North and South Platte basins have experienced the highest levels of precipitation in the state, at 90 and 81 percent, respectively. While the Yampa & White and Colorado River Basins are slightly lower at 80 percent. The southern half of the state has been significantly drier with the Southwest basins of the San Miguel, Dolores, Animas & San Juan, Rio Grande, Gunnison and Arkansas all well below normal precipitation at 54, 54, 61 and 58 percent respectively.
  • Many basins’ year –to-date precipitation, based on SNOTEL is tracking near 2002, as is the state as a whole.
  • 74 percent of the state is in some level of drought classification with 24 percent in moderate drought, 30 percent in severe drought and 20 percent classified as extremely dry. An additional 16 percent of the state is experiencing abnormally dry conditions (see image on reverse side).
  • Reservoir storage statewide is at 116 percent of normal, with all basins above average. The Arkansas basin is reporting the highest average storage at 145 percent. The Southwest basins of the San Miguel, Dolores, Animas & San Juan have the lowest storage levels in the state at 105 percent of normal.
  • The Surface Water Supply Index(SWSI) values improved slightly for March 1, but remain below normal with much of the western slope classified as moderate to extremely dry. These values are expected to decline when new numbers are released on April 1, this is largely the due to below average streamflow forecasts.
  • Streamflow forecasts are well below average for the vast majority of the state and near normal in isolated areas including the Blue River, St. Vrain and Cache La Poudre basins (see image on reverse side).
  • Short term forecasts show that temperatures will be more seasonal with a normal chance of precipitation, however longer term forecasts indicate increased likelihood of below average precipitation and above average temperatures.
  • A weak La Niña remains active and is projected to transition to neutral conditions in May or June, indicating that warm and dry conditions are likely to persist through the spring. While the monsoonal rainfall forecast is still uncertain, above average temperatures should continue into the summer months.
  • Statewide Basin High/Low graph March 25, 2018 via the NRCS.

    Statewide SNOTEL snowpack is well below average at [72] percent of normal, and tracking close to 2002 levels. To reach a normal snowpack peak we would need to 480 percent of normal accumulation. Snowpack typically peaks in early to mid April.

    March 1 streamflow forecasts are below 60 percent of average for nearly all of southern Colorado, while the central portion of the state ranges from 70-80 percent of average. With dry conditions throughout March the April 1 streamflow forecasts are projected to decline.

    Click here to read the current drought assessment from the Colorado Climate Center. Click here to go to the NIDIS website hosted by the Colorado Climate Center.

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