From The Mountain Town News (Allen Best):
Peak runoff has come and gone in many places of the West, weeks if not a full month earlier than the long-term average. It comports with a trend.
In northwest Colorado, the snowpack in the Yampa River drainage around Steamboat Springs, typically peaks on about April 10. This year, reports the Steamboat Today, the snowpack peaked March 12.
In Idaho’s Wood River Valley, the winter’s snows melted in a hurry in early May. The flood in Ketchum, at the base of the Sun Valley ski lifts, was regarded as the largest in 101 years of recorded history.
What was notable, says the Idaho Mountain Express, is both the volume of water and the runoff in early May.
Oregon State University climate scientists John Stevenson told the Express that it’s “really difficult to judge any one year” to be a result of rising global temperatures.
“That’s one of the challenges we run into in the science world where people say, ‘Oh, it’s climate change.’ We’re not at the point where we can take any one random event and say it’s climate change.”
That said, his 2015 study concluded that the point each spring when half of the water year’s streamflow had run off was occurring an average 1.9 days earlier per decades.
But more extreme events are happening with greater frequency, said Mark Davidson, director of conservation initiatives with The Nature Conservancy. He pointed out that the Big Wood River has had two 100-year floods in the last 15 yeas.
What caused the early-May flooding in the Sun Valley area? Hot temperatures, 6 to 13 degrees warmer than the normal average temperatures during the early days of May as compared to the last several decades.
In Colorado, Aspen officials continue to discuss how to make the city more resilient in the face of long-term climate change. Decades ago, the city filed for water rights on two creeks, including the potential for building dams. That’s not popular in Aspen, and so the city commissioned a study about whether the old mines in Aspen and Smuggler mountains could be used to store water in lieu of dams.
The $15,000 answer: yes, it can be done, but it would be costly and without precedent in Colorado. The better option seems to be aquifer recharge, to be tapped in time of drought. But it also comes with some risks.