#Snowpack/#Runoff news: #Snowmelt timing dictates #whitewater season, folks are hopeful

Colorado River Basin High/Low graph April 10, 2019 via the NRCS.

From The Glenwood Springs Post Independent (Laurie Rink):

As of the beginning of April, snowpack in the Upper Colorado River basin sits at 130 perfect of normal. Snowpack conditions are well above where they were a year ago when we were wondering if western Colorado rivers would be boatable at all. Accumulating abundant snowpack over the course of the winter is important because it represents a temporary savings account that will be drawn upon for the remainder of the spring, summer and fall. his savings account provides our everyday drinking water, irrigation water for agricultural, in-channel flows that support fish and other wildlife, and the water we enjoy for river recreating.

Mother Nature, however, is largely in control of how quickly the water savings account is drawn down. As snow melts in the high country, the runoff makes its way down the rivers and streams of the Western Slope, with peak flow typically occurring during the months of May and June in the Colorado River. The timing of peaking flows and the volume of water that finds its way to rivers and streams is influenced by a number of factors. Conventional wisdom is that warm air temperatures and sunny days have a strong influence on the rate of snowmelt. Newer evidence is showing that human-induced factors are starting to shift historic patterns.

Researchers from Colorado State University have found that the timing and volume of runoff in the Colorado River is shifting due to higher temperatures now common in the basin, a result of human caused climate change. The phenomena of dust on snow, or the accumulation of blowing dust that settles on the surface of the snowpack, can also play a role by melting snow earlier.

Because of ongoing drought conditions and the notable lack of precipitation in 2018, soil moisture content in the Upper Colorado going in to the winter months ranged from 70 percent below average to less than 30 percent below average. Melting snow will need to replenish soil moisture before runoff occurs. In addition, many of the state’s reservoirs were depleted after the low water year of 2018. The net effect of these influences could mean a reduced peak streamflow and an overall reduced volume of water.

Nonetheless, there is plenty of reason to enjoy the bounty of this year’s anticipated runoff.

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