From The Vail Daily (Scott Miller):
In a memo to the district’s elected board, communications and public affairs manager Diane Johnson wrote that streamflows measured on Gore Creek, the Eagle River near Minturn and the Eagle River at Avon are all running significantly below seasonal norms.
As of July 22:
• Gore Creek was running at 36 cubic feet per second, 38 percent of the normal flow.
• The Eagle River near Minturn was running at 49 cfs, 43 percent of normal.
• The river at Avon was running at 108 cfs, 36 percent of normal.
Those readings are among the lowest on record. Only the drought years of 2002 and 2012 showed lower streamflows from April 1 to July 22. Even in those drought years, the graph lines show the occasional bump, when rainfall temporarily boosted streamflows.
This year, those bumps haven’t developed.
THE MISSING MONSOON
The short boosts to streamflow in those other years started coming in about mid-June, the result of the annual “monsoon” flow that generally brings some significant moisture to the area.
The U.S. Climate Prediction Center in late spring predicted a better-than-average change of precipitation into the summer. That hasn’t developed so far this year.
Tom Renwick, a forecaster at the Grand Junction office of the National Weather Service, said the monsoonal flow in Western Colorado usually develops when a high-pressure system sets up over Texas and Oklahoma and a low-pressure system develops over the desert Southwest United States. When that happens, moisture is sucked up from the south and ends up being deposited in Western Colorado.
Renwick said high pressure has been setting up in the wrong place so far this year.
That high pressure usually means dry conditions. At the moment, high pressure is farther west than it needs to be to bring rain.
“It’s basically on top of us,” Renwick said.
While Western Colorado hasn’t been getting its usual summer rainfall, Renwick said other areas are seeing seasonal precipitation. The monsoons have hit Mexico.
CONCERN FOR AQUATIC LIFE
Locally, the lack of the monsoon rains is starting to concern water providers.
In an email, Johnson wrote that the district and other water providers “are now back to a bit worried about how our streams will do during the normal low-flow months of August on.”
That said, there are adequate supplies for domestic use.
Aquatic life can be hard-hit by low streamflows, especially when those low flows are combined with warm temperatures.
Colorado Parks and Wildlife last week called for a voluntary fishing closure on portions of the Eagle, Colorado, Crystal and Roaring Fork rivers. Anglers are asked to stop fishing from 2 p.m. to midnight on stretches of those streams. Water temperatures near or above 70 degrees Fahrenheit can be damaging to fish that are caught and released back into the water.
Rainfall and cooler water temperatures are good for both aquatic life and landscaping. Until those rains come, though, district customers are being asked to let their landscaping dry out a bit.
When the monsoonal flow might develop remains an open question, but Renwick said he’s optimistic.
There’s a possible monsoonal pattern developing later this week for New Mexico, the Front Range and parts of Wyoming, but not Western Colorado.