Western Water Assessment
@wwanews
WWA is an applied research program that addresses societal vulnerabilities related to weather and water resources.
At the end of July, #streamflow was below average for most regional rivers. On July 29, record-low daily streamflow was recorded at 29 sites in Colorado, 10 sites in Utah, and four in Wyoming, including the Arkansas, Dolores, Eagle, Roaring Fork, South Platte, Uncompahgre, and Yampa Rivers.
July #temperatures were above average (+2-4ºF) for the entire region, with much above average temperatures (+4-8ºF) across much of Wyoming, northern Colorado, and northeastern Utah. Learn more: wwa.colorado.edu/resources/in... @cires.colorado.edu
#ElNiño is favored to persist through early spring 2027, with an 81% chance of a very strong El Niño from October-December 2026. Learn more: wwa.colorado.edu/resources/in... @cires.colorado.edu
Pacific Ocean temperatures transitioned to #ElNiño conditions in June. Observed sea surface temperature anomalies were approximately +1.2 °C above average in the Niño 3.4 region, indicating a moderate El Niño. El Niño is favored to persist through winter 2026-27. wwa.colorado.edu/resources/in...
In WWA's recent webinar, WWA research scientists Seth Arens and Nels Bjarke provide an update on the 2025-2026 Intermountain West snow drought, followed by an overview of the Western Drought Perspective Tool and the research supporting it. Watch here: wwa.colorado.edu/outreach/eve... #snowdrought
June 1 regional seasonal #streamflow volume forecasts were less than 50% of average for all river basins except the Wind (93%), Shoshone (87%), Yellowstone (80%), Snake (73%), and Bighorn (61%) River Basins. Learn more: wwa.colorado.edu/resources/in... @cires.colorado.edu
WWA's latest rapid assessment is on the 2025-2026 extreme #snowdrought in CO, UT, and WY. The assessment covers the magnitude of extreme low snow-water equivalent (SWE) conditions in early 2026, likely causes of the snow drought, and more. wwa.colorado.edu/resources/ha... @cires.colorado.edu
In Colorado, seasonal #streamflow volume forecasts suggest 20-40% of average runoff for all major river basins. In Utah, forecasts suggest 10-40% of average runoff for all major river basins. In Wyoming, forecasts were more variable. Learn more: wwa.colorado.edu/resources/in... @cires.colorado.edu
The #heatwave during March 2026 was unprecedented in the western U.S. temperature records since 1895. March 2026 average temperatures shattered records in Colorado (by 4.3ºF), Utah (by 5.5ºF), and Wyoming (by 2ºF). Learn more: wwa.colorado.edu/resources/in... @cires.colorado.edu
Colorado and Wyoming experienced the warmest February on record, and Utah experienced the third warmest February on record. All three states experienced the warmest meteorological winter (December-February) on record. Learn more: wwa.colorado.edu/resources/in... @cires.colorado.edu #temp #wx
Regional #snowpack and #streamflow volume forecasts are extremely low. Record-low statewide snowpack conditions exist in Colorado and Utah, while Wyoming statewide SWE is 84% of average. Learn more: wwa.colorado.edu/resources/in... #wx #weather @cires.colorado.edu
The entire region experienced much above average (top 10%) to record-warm #temperatures in December. For weather monitoring sites with at least 50 years of data, 50 of 60 sites in Utah had a record-warm December, 31 of 75 sites had records in Colorado, and 34 of 46 sites had records in Wyoming. #wx
High temperatures coupled with mostly below normal precipitation caused low snow-water equivalent (SWE) and worsening drought conditions in November. Learn more: wwa.colorado.edu/resources/in... @cires.colorado.edu #wx #weather #snowpack #drought
Large areas of the region received 150-200% of normal #precipitation in October, with some locations in northern Utah, southeastern Utah, northern Wyoming, and southwestern Colorado receiving 200-400% of normal precipitation. Learn more: wwa.colorado.edu/resources/in... @cires.colorado.edu
#Drought conditions improved during September in Colorado and Wyoming, while all of Utah continues to remain in at least moderate (D1) drought. By Sept 30, regional drought coverage was 61%, a 6% improvement since the end of August. Learn more: wwa.colorado.edu/resources/in... @cires.colorado.edu
“Whenever an organization like WWA brings communities into this discussion, you can see a lot of cascading benefits from that,” says sustainability consultant Gwen Garcelon, speaking about the #drought resilience workshop that WWA held in Carbondale in 2018. Learn more: wwa.colorado.edu/impacts
Monthly #streamflow conditions were below to much below normal across large parts of the region during August. Most river basins in Colorado and Utah experienced these conditions, with record-low monthly streamflow observed in the Piedra River and at four streamflow gauges on the White River.
Regional #drought conditions expanded and worsened, especially near the Colorado-Utah border and western Wyoming, where extreme (D3) drought conditions now cover 23% of the region. Learn more: wwa.colorado.edu/resources/in... @cires.colorado.edu
Are you an undergrad student @colorado.edu interested in water? Apply by 9/8 for the Colorado Water Fellows Program, hosted by WWA! The program prepares students for careers in the water field and connects them to opportunities, including conferences. Apply here: forms.gle/4DdZdFkufmon...
In July, regional precipitation was generally below normal, with record-dry conditions throughout much of the region. As of August 1, Colorado reservoirs are 63% full, Utah reservoirs are 75% full, and Wyoming reservoirs are 72% full. Learn more: wwa.colorado.edu/resources/in... @cires.colorado.edu
During June, much of the region experienced above average temperatures and below average precipitation. As of July 1, seasonal snowmelt was completed with many mountain locations melting out 1-2 weeks earlier than average. Seasonal streamflow volume forecasts remained below to much below normal.
As of June 1, statewide percent median SWE was 54% in Colorado, 29% in Utah, and 62% in Wyoming. Seasonal streamflow volume forecasts are all below to much below average for the region. Regional drought coverage in late May was 53%. Learn more: wwa.colorado.edu/resources/in...
In April, regional precipitation was below to much below normal with some areas experiencing record-dry conditions. As of May 1, statewide percent median SWE was 58% in Colorado, 66% in Utah, and 86% in Wyoming. Learn more: wwa.colorado.edu/resources/in...
End of April #snow water equivalent (SWE) is below to much below normal for the majority of the region (CO, UT, WY), with less than 50% of median conditions in southern Colorado, southern and western Utah, and northeastern Wyoming. wwa.colorado.edu/resources/in...
WWA's Katie Clifford spent time last week with CLIMAS collaborators Christina Greene and Becky Patterson-Markowitz to kick off their project examining the long-term wildfire recovery challenges in rural communities in Colorado, New Mexico, and Arizona. wwa.colorado.edu/research/pro...
Mid-April #snow water equivalent (SWE) is below to much below normal for the majority of the region (CO, UT, WY), with less than 50% of median conditions in southern Utah, southwestern Colorado, and northeastern Wyoming. wwa.colorado.edu/resources/in...
April 1 seasonal (April-July) #streamflow volume forecasts were near-to-below average across the region. Seasonal streamflow is forecasted at 67% of average for Lake Powell. Learn more: wwa.colorado.edu/resources/in...
Seasonal #streamflow volume forecasts are below to much below average for all Colorado and Great Basin rivers except the headwaters of the Colorado and Yampa Rivers. Learn more: wwa.colorado.edu/resources/in...