Colorado Water Supply Forecasts Remain Well Below Median Following Early Melt

Denver, CO - May 8, 2026 - Colorado's 2026 water year this far has been defined by records across nearly every metric: an anomalously early snowpack peak, rapid melt driven by record March temperatures, snowpack that tracked at-or-near the lowest values in the SNOTEL period of record from January through May 1, and near-record early season precipitation in the San Juan Mountains. Runoff has arrived weeks ahead of the historical median across river systems and recession is largely underway.

May through July runoff forecasts remain low across Colorado at 24 percent of median at the 50 percent exceedance forecast. Western slope forecasts range from 22 to 24 percent of median and eastern basins remain slightly higher at 37 percent in the South Platte basin and 33 percent in the Arkansas basin (Figure 1). The Upper Rio Grande basin is forecast 30 percent of median at the 50 percent exceedance. Forty-eight of 86 forecast points rank as either the lowest or second lowest in their period of record. All 86 forecast points rank at or below the 13th percentile with a median percentile rank of 2. Several Colorado Headwaters forecast points rank lowest on record, including Colorado River near Cameo forecast a departure of 1.49 million acre-feet (MAF), rank 1 of 73 years.

Figure 1. Primary period streamflow forecast volume at the 50 percent exceedance probability, percent NRCS 1991-2020 median, May 1, 2026.

Statewide snowpack is 20 percent of median as of May 1, effectively unchanged from April 1 despite near-normal April precipitation. Snowpack peaked in early March in southern basins and mid-March in northern basins, three to five weeks ahead of historical median peak timing at half of median peak snow water equivalent (SWE). Early May storms have boosted statewide snowpack to 25 percent of median as of May 7, with sites in the Front Range east of the Continental Divide being particularly favored and receiving near 2 inches of SWE.

Many observed streamflow hydrographs are already entering recession unusually early. On the Yampa River near Maybell, seasonal peak flow occurred at the end of March and ranks as the earliest peak date and lowest peak in the 110-year period of record. Similar early and shortened hydrographs have developed in the Upper Colorado Region and in southern basins as accelerated spring melt caused much of the seasonal runoff to occur earlier than normal.

Statewide reservoir storage is 85 percent of median, while forecast inflows into Colorado's largest reservoirs are well below median. Forecast inflows for the May-July 50 percent exceedance outlook range from 17 percent of median at McPhee Reservoir and 18 percent Blue Mesa to 36 percent at Lake Granby and Pueblo Reservoir.

April storms briefly stabilized snowpack conditions but did not offset the impacts of the record warm and dry winter and the late March heat wave that accelerated snowmelt and shifted runoff weeks ahead of normal. Future weather remains a source of uncertainty and the current 8-14 day outlooks favor above-normal precipitation alongside above-normal temperatures statewide.

Colorado's Snowpack and Reservoir Storage as of May 1, 2026

^{* combined San Miguel-Dolores-Animas-San Juan River basin}

For more details see the May 1, 2026 Water Supply Outlook Report.