February Storms Brought Needed Snow, but Early Warmth Limits Seasonal Recovery

Denver, CO - March 6th, 2026 - Statewide snow water equivalent (SWE) improved during February following multiple storm systems, increasing seasonal accumulation from 53 percent of the 1991-2020 median earlier in the month to 60 percent of median by month's end. Climatologically, February contributes about 17 percent of total seasonal SWE, while March contributes approximately 16 percent, together accounting for roughly one-third of the seasonal snowpack buildup. March and April typically represent the final opportunity for material snowpack recovery prior to the onset of melt. Median March accumulation is 3.015 inches, meaning a near normal March alone would not bring snowpack back to median levels.

Through February, 82 percent of median precipitation has produced only 62 percent of median SWE, reflecting a lower-than-normal conversion of precipitation into stored mountain snowpack. Much of this divergence occurred early in the water year. Historical median October SWE accumulation is approximately 1.27 inches statewide, while water year 2026 accumulated only 0.39 inches despite receiving 3.46 inches of precipitation. This corresponds to roughly about a 1:9 precipitation to SWE ratio. Early season rainfall, particularly in October within the San Miguel-Dolores-Animas-San Juan (SMDASJ) basins, generated immediate runoff contributions rather than delayed meltwater. The approximately 12-foot rise at Navajo Reservoir reflects this front-loaded response. While beneficial for near term storage conditions, such inflows do not provide the sustained release characteristics of snowmelt driven hydrographs. As a result, reservoir storage metrics may appear relatively stable in aggregate (87 percent of median statewide), yet the underlying water supply outlook remains sensitive to late season snow accumulation.

Figure 1. Colorado basin level April-July streamflow forecasts at the 50 percent exceedance probability as of March 1, 2026.

Basin level streamflow forecasts reflect the limited hydrologic response to February storms (Figure 1). While February produced the largest monthly additions to snowpack this season, those accumulations were not sufficient to offset November - January shortfalls. As a result, forecast improvements were modest and uneven across the state. At the 50 percent exceedance probability, the statewide median April-July forecast is 58 percent of median. Most basins experienced downward adjustments between the February 1 and March 1 forecasts, including the Colorado Headwaters (58 to 56 percent), Gunnison (64 to 60 percent), Upper Rio Grande (60 to 56 percent), and Arkansas (63 to 57 percent). The South Platte continues to track higher than the rest of the state and remains at 76 percent of median. In contrast, the Laramie-North Platte basin remains the most constrained with runoff projections at 51 percent of median. Taken together these forecasts indicate that February snowfall helped stabilize seasonal runoff expectations but did not materially shift the statewide water supply outlook. Without sustained accumulation through March and April, forecasts are likely to remain below typical levels for the 2026 water year. In southern basins such as the SMDASJ and URG, a meaningful portion of annual precipitation also occurs during the North American monsoon. Historical distributions observe around 30 percent of annual precipitation falls between June and September and contribute to late season reservoir inflows but typically arrives after the primary snowmelt driven irrigation demand period.

Another consideration is soil moisture antecedent conditions. Early rainfall events partially recharged upper soil profiles in southern basins. However, if late season snowfall remains limited, runoff efficiency during melt could decline as soils absorb a portion of the initial meltwater. Conversely, where soils are near saturation, a rapid melt scenario under warm spring conditions could compress the runoff window and increase short duration flow peaks while limiting volume. The timing and persistence of cold conditions through March will therefore influence both peak SWE and runoff shape.

Colorado's Snowpack and Reservoir Storage as of March 1^st, 2026

* San Miguel-Dolores-Animas-San Juan River basin

* *For more detailed information about mountain snowpack refer to the Colorado Water Supply Outlook Report.For the most up to date information about Colorado snowpack and water supply related information, refer to the Colorado Snow Survey website.