If there is a single certainty to the erratic endeavor of predicting flow levels of Colorado whitewater, it is that nothing is for certain. Ever. There are too many variables.
Since Colorado draws the majority of its river water from snowmelt, there is the matter of not only how much snow falls, but where and when. Temperature plays an equal role, with warmer winters diminishing snowpack almost as quickly as it falls, slower thaws delivering a subtle crescendo of smaller flows for longer spans of time. How rapid and consistent the spring warming occurs tends to determine when the rivers will peak. Then there’s the whole matter of storage, temporary plugs in the system known as reservoirs.
So given the configuration of said variables as we enter Colorado’s river running season at the midway point in May, the certain uncertainty theory appears to have proved itself in the most cyclically devious of manners.
This time, experts say, the prediction is a lock: Big water is virtually assured nearly everywhere in the state. And it’s likely to stick around for a while.
“This is the most water out of the snowpack we’ve gotten in the last 10 years or so,” said Tom Pagano, a Colorado water supply forecaster from the Portland, Ore., office of the USDA’s National Water and Climate Center. “For river runners, it’s going to be kind of great all around.”
As gamblers go, Pagano is a numbers man, a figurative card counter measuring the depth and moisture content of Colorado snowpack feeding various river basins throughout the year through the Natural Resources Conservation Service’s ongoing survey known as Snowpack Telemetry, or SNOTEL. After crunching the data and presenting it in a color-coded chart and graph, well, you don’t need the “rain man” to calculate the results this time around.
“The action is definitely coming,” Pagano said.
The numbers in each of Colorado’s major river basins speak for themselves, not only in terms of accumulated precipitation but in the associated “snow-water equivalent” as well. Using the Upper Colorado River basin as an example, the amount of precipitation feeding it lingered at 119 percent of the 30-year average on Monday. More significant, the amount of water that forecasters expect to get out of that snow remains at more than 140 percent of the average. Similar figures hold true for the Gunnison and Arkansas river basins, setting the table for a whitewater paddling season the likes of which Colorado has not seen in years.
“Water content was real good in a lot of places. Not just the (snow) depth, but the amount of moisture in it,” said Tom Kleinschnitz, owner of Grand Junction’s Adventure Bound River Expeditions and president of the 55-member Colorado River Outfitters Association. “It looks like things are going to get real exciting.”
Oddly, the secret ingredient in this year’s predicted blue-ribbon runoff is not the heat. At least not yet. Rather, it has been the cold, up to and including last weekend’s high country snowstorm that dropped as much as a foot of snow in the central mountains (with more in the immediate forecast). Before the season’s record snowfall has time to melt, it replenishes itself, with a healthy portion preserved by uncommonly cold temperatures during the past five months.
“That’s the thing that’s a bit unusual. This year has been quite cold, and the snowpack is really hanging in there,” Pagano said. “We’re just waiting for a trigger.”
Jan Curtis, the National Water and Climate Center’s in-house climatologist, said that trigger could be pulled by the end of the week when a strong ridge of high pressure is forecast over the West and temperatures in the Rocky Mountains are expected to increase by 15 degrees.
A proactive approach from Colorado water managers making space for the inevitable cache in reservoirs statewide also bodes well for recreational river enthusiasts. With several of the state’s water reserves already brimming, even heavily dammed rivers such as the South Platte are expected to run as if they remained wild while the gush of snowmelt flows directly through dams to the tailwaters below.
“Flows are going to get really big,” said Dave Bennett, a water resource planner for Denver Water. “Everything will be flowing straight down. All the water out of Cheesman should come straight through to Chatfield. There’ll be a lot of water through Denver during runoff.”
With his West Slope commercial rafting staples of the Colorado, Gunnison and Yampa rivers showing the first signs of life in the state so far, Kleinschnitz has had his guides rehearsing for the big show for several weeks.
It’s been nearly 25 years since flows on the Yampa hit a record 33,200 cubic feet per second (May 18, 1984) and combined with flows of the Colorado River downstream at Cataract Canyon to peak at a burly 125,000 cfs. Already a call has gone out from rangers at Cataract’s surrounding Canyonlands National Park for volunteer river safety support below the canyon’s notorious “Big Drops” when the flows broach the anticipated 50,000 cfs level later this month. Lake Powell, at the canyon’s end, is forecast to rise 50 feet over the course of the runoff.
“I’ve been telling my guides to get their bodies ready,” Kleinschnitz said. “Physically, you want to be at the top of your game. Because when it comes, away we go.”
