Latest Colorado storms push annual snowpacks to above-average level
May 11, 2016
The recent snowfall has been a blessing for the region's resorts and those who frequent the mountains to ski and ride, but it's also helping the state play catch up in meeting growing water needs once the spring thaw begins.
A relatively dry February and March in Summit County following a strong start to the 2015-16 ski season resulted in slightly below-average snowpacks. Area percentages of customary levels have varied from between the mid-80s to mid-90s ahead of this week's storms, which delivered more than two feet of fresh snow over 72 hours in some areas. That's led to an immediate impact and quickly bumped snowpack to greater than average levels at this point of the winter.
It's important to the entire state that this precipitation arrives before too long or it won't have the desired effect of satisfying its late-spring and early-summer water demands.
"In a normal year, past the beginning of May, that's when you're not really seeing as much influence from snowpack accumulation," said Karl Wetlaufer, assistant snow survey supervisor at the Natural Resources Conservation Service (NRCS). "You typically see that big peak in streamflow in late-May or early-June, about a month after the highest snowpack, more or less."
That normal quota is critical for providing necessary water supplies for the multitude of uses throughout Colorado, as well as its neighboring states. Those uses range from drinking water and irrigation for farms to recreational activities such as fishing and rafting, even to hydroelectricity at the Glen Canyon Dam on Lake Powell in northern Arizona where the Colorado River heads before ultimately flowing into Mexico's Gulf of California.
"Lake Powell is the ultimate barometer," said Jim Pokrandt, chair of the Colorado Basin Roundtable and director of community affairs for the Colorado River Water Conservation District. "It's the savings account by which we meet Lower Basin obligations and the big measure of how our water supply is."
The Colorado River, which runs through parts of seven states, is divided into the Upper and Lower basins via the Colorado River Compact. In the Upper are Colorado and Wyoming, and in the Lower are California and Nevada, with the two sharing portions of Arizona, New Mexico and Utah.
"We're snow farmers," added Pokrandt. "We follow snowpack figures because the snowpack crop is what feeds the Colorado River, which feeds the West. It's vitally important we raise a good crop each year."
Traditionally, the annual snowpack is built through mid-to-late-April, so there's still time to reach routine levels. Even so, while most of Summit County's measuring sites at Loveland Ski Area, Arapahoe Basin, Copper Mountain, Hoosier Pass and Summit Ranch are now each above 100-percent levels, many other portions of the state remain a shade under average totals.
According to the NRCS, the statewide Snow Water Equivalent (SWE) as of Thursday, March 17, was 95 percent of median levels. That missing 5 percent is not of major concern, so long as future weather conditions stay consistent.
"At this point, we are more and more confident as the days go by that we're in pretty good shape as far as snowpack from a streamflow standpoint," said Wetlaufer. "If the proverbial faucets turned off right now and there was no more snowpack, then we'd see lower levels. But it's pretty likely that we'll continue to get more precipitation in next month or so, and it's looking encouraging."
That in mind, during the 16-year period between 2000-15, the Upper Colorado River Basin has seen dramatic volatility in its levels from year to year, often presenting a state of drought. The record low came in 2002, when the inflow to Lake Powell was just 24 percent of an average water year, and both 2012 and 2013 registered below 50 percent.
In only three of those 16 years have water levels come in at above average, the last one occurring in 2011 at 147 percent compared to regular levels. The current projection for 2016 is about 92-percent inflow to this strong measure of overall hydrologic conditions, which nearly matches the 2015 number of 94 percent.
"The ultimate fear is that this pattern continues over time, and we could be looking at Colorado River Compact obligation complications," said Pokrandt of the amount of this integral water source allocated to each state. "In the bigger picture, if this long-term drought continues, Lake Powell will be lowered to the point of no electric power, and the turbines won't be able to operate. But if we can avert that, we avert compact crisis."
Heavy snowpack years — which the state could still be heading toward depending entirely on how the rest of the winter and spring weather materializes — actually result in oversupplies of water and is ideal. Those circumstances help establish higher water levels in many of these major headwaters that all leave the state, the Platte, Rio Grande and Arkansas, aside from the Colorado, and are a benefit to all states that utilize these sources.
"In general, a surplus leads to a lot less disagreements in the long run," said Wetlaufer, "as opposed to a year where we are below normal, which is when those issues get a lot more contentious and people want to make sure they get their fair share. This year seems to be a pretty near-normal snowpack, especially around Summit County, and we should be in good shape for an ample water supply … and in a good place overall."