Colorado weather outlook
January 27, 2012
For farmers hoping to hear climatologist Nolan Doesken forecast a great rebound for Colorado’s below-average snowpack, such a prediction never came out of his mouth Wednesday, Jan. 25.
Doesken, delivering his “State of the Climate” report to an audience at the Colorado Farm Show in Greeley, CO, said past weather trends have led experts to anticipate warm and possibly dry weather across the state through the spring – although “accurately predicting precipitation that far ahead of time is difficult.”
According to the Natural Resources Conservation Service, Colorado is now 26 percent below average in terms of its statewide snowpack – after having stood at 28 percent behind the norm on Jan. 1.
“We’ve had some snow recently that’s helped us rebound a bit, but we’re still a ways behind … and nowhere near where we were a year ago,” Doesken said, reflecting back to the winter and spring of 2011, when snowpack numbers were well above normal.
As Doesken explained, most of the snowfall in the mountains doesn’t come until March and April. Last year, it wasn’t until the second week of April that the heavy snowfall came, he said during his presentation Wednesday.
But the persisting La Nina weather patterns make it tough for forecasters to predict big snows this spring, he added. La Nina patterns traditionally result in dry weather, even bringing on drought in some areas – as it did in Texas this past year.
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A U.S. map presented by Doesken on Wednesday showed the next three months to be generally warm and dry in Colorado.
“It doesn’t give us a prediction that’s clean cut, but the La Nina pattern is a useful indicator,” Doesken said.
During the past month, snowpack in the Colorado River Basin has increased by 7 percent, and now sits at 30 percent behind the average. On Jan. 1, when the Colorado River Basin’s snowpack was 37 percent below average, that marked the second-lowest level for the basin on that day – going back to when records started being kept in the 1980s.
While much of the state has seen some improvement during the month of January, the South Platte River has taken a step backward, with its snowpack 19 percent below average Wednesday after it was 15 percent below average on Jan. 1.
Snowpack for the South Platte and Colorado river basins is the source of most of the water used by northern Colorado municipalities and farmers. The snowpack that accumulates in the mountains during the winter and then melts and flows downhill starting in the spring makes up about 80 percent to 90 percent of the water that sits in the South Platte and Colorado river basins.
While the Colorado River flows from the mountains in the opposite direction of Greeley and Weld County, the river makes up a sizeable portion of the water that goes into the Colorado-Big Thompson River Project – which transports Colorado River water from the Eastern Slope and flows to more than 640,000 acres of irrigated farm and ranch land and to about 850,000 people in eight northern Colorado counties. A 13.1-mile tunnel beneath Rocky Mountain National Park is used to bring the Colorado River water to the east side of the Great Divide.
While there is some concern about the current low snowpack across the state, Doesken explained that the amount of water being stored in northern Colorado reservoirs and other storage facilities is still at healthy levels because of last year’s above-average snowpack.
While some farmers can depend on that stored water to irrigate their crops later this year, dry weather could cause problems for dryland wheat farmers and others who plant crops that don’t use irrigation.
Reprinted with permission from Greeley (CO) Tribune.