CODOS UPDATE june 1, 2024: rising peaks

Greetings from Silverton,

Many stream gauges in Colorado show a similar pattern for this past month. Following our statewide codos tour May 10-13, during which we observed wet snow accumulation and rain across Colorado, dust once again found it’s way to the surface and streamflows began surging. Fortunately, a period of about a week brought blustery, mild precip, and cooler weather that tapped the brakes on streamflows. Nighttime temperatures were chili - we had a fire in the wood stove every evening. Minimum temperatures in the mountains were about 4-8 degrees F below normal for that period (see below). This “timeout” week really looks to have helped push peak streamflows (more so for the Southern Basins) more toward the normal timeframe (or at least extend higher flows). Summer marches closer, we are now in the month of June, and the forecast for the mountains this week is 0.50” precip or less. The NWS temperature forecast is for above normal temps this weekend and even higher by mid-week. Expect streamflows to continue to rise.

Snow has been melting quickly at Swamp Angel (11,060’) which now has about 5” of snow depth remaining near the station. Senator Beck station (12,200’) still has a fair amount at 31.5” depth. Typically for the watersheds around Red Mt Pass, the first peak occurs when the majority of snow melts at the 11,000’ band and lower, and second peak when the higher elevations melt out. The average SWE remaining at Snotel stations for the Southwest Basins is essentially none (see below). But remember that in the Upper Colorado River Basin about 40% of streamflow is generated above all Snotel stations and 50% of streamflow is generated above ~9,900’.

Take Care,

Jeff Derry

Below: Streamflow, albedo, and max/min temps for a few select rivers.