A hot spell for the books is back
Ten years ago last weekend, after flying over several wildfires burning across Colorado, then-Gov. Bill Owens made an observation that still resonates.
“It looks as if all of Colorado is burning today,” Owens told reporters then.
While the number and size of fires torching the state this week pale in comparison, many of the factors that converged a decade ago to create the worst wildfire season in Colorado’s history and worst drought in recent memory are in place again today. An abnormally warm and dry winter and spring, low streamflows, high and frequent spring winds, high temperatures and rapid snowmelt have brought drought back to the state a decade later.
In its monthly water report for June 2002, the Natural Resources Conservation Service indicated that water year “will be one for the books for some time to come.”
“One of the lowest snowpack accumulations in decades, followed by one of the driest springs in many years, all on the heels of several previous dry years, contributing to below average reservoir storage and dry soils.”
Who knew that “some time” would end up referring to only 10 years?
To be sure, many measurements of the state and impact of the current drought are below where they were in 2002. And last year’s above-average snowpack left the region’s reservoirs filled and well-equipped to deal with the small snowpack and early spring of this year.
But this month’s edition of the same water supply report starts in an eerily familiar way: “The 2012 water year is definitely one that will be remembered for quite some time,” it said before adding later, “The only part of the equation separating this year from conditions in 2002 is reservoir storage.”
Snowpack in the basin was far below average this winter and, in many places, has already completely melted. At Mesa Lakes, peak snowpack occurred around mid-March this spring. It typically peaks around mid-April and last year did not peak until late May, according to data collected by the NRCS. The same conditions held true throughout most of the Upper Colorado, Gunnison and other basins.
What snow did come this year went fast — by early May. Last year, it melted off around early June and on average it usually does not melt off until late June, according to the same data.
“In the end this season saw the lowest statewide snowpack accumulation since 2002 and in some basins, this year became the new minimum on record,” the NRCS wrote in its June water supply report.
Wendy Ryan, a research associate with the Colorado Climate Center, said this winter was expected to be drier than last since the second year of a La Nina episode — as this winter was — is usually drier than the first.
“But we didn’t know it was going to be this much less,” she said.
The sparse snowmelt created Colorado and Gunnison river streamflows a fraction of where they typically are at this time of year. In the Upper Colorado River Basin as a whole, 87 percent of USGS stream gauges were recording below normal flows as of Sunday, according to a drought assessment summary put out by CSU’s Colorado Climate Center on Tuesday.
“It’s a dry year, to say the least,” said David Brown, chief of the USGS Grand Junction office.
Luckily, last year’s generous snowpack has left many of the region’s reservoirs much better off than they were in the spring of 2002. Though daily inflows into major reservoirs remain lower than they typically would be at this time of year due to this spring’s small snowpack and early snowmelt, the actual reservoir volumes are generally solid.
Grand Junction’s two major reservoirs, for instance, Juniata and Purdy, currently hold a combined 7,724 acre feet, according to Terry Franklin, the city’s deputy utility director. At this time in 2002, their combined total was 5,905 acre feet, although 400 acre feet in additional capacity has since been added to Juniata.
Franklin also noted that though the rate at which residents are consuming water is up compared to last year, that rate is actually below where it was in 2002. He said he does not expect those reservoirs to drop more than a couple thousand acre feet this year, probably no lower than about 5,500 acre feet. In 2002, he said, their combined total went as low as 3,650 acre feet.
“We’re in really good shape as far as our reservoirs are concerned,” he said.
According to the Grand Valley utilities’ drought response plan, some mandatory water use restrictions would be imposed for Grand Junction residents only once Juniata and Purdy reservoirs were anticipated to fall to 50 percent of their storage capacity.
HOT AND DRY
For the month of May, much of the Western Slope and eastern Utah received less than 20 percent of average precipitation.
The average year-to-date precipitation for Grand Junction since 1981 is 4.04 inches, according to the National Weather Service. Through Wednesday, the city had only received 1.38 inches, slightly less than the 1.67 it had by that date in 2002.
The city also saw an abnormally toasty late spring this year, with the number of 90-degree days virtually equaling 2002.
A PERFECT STORM
The high temperatures and lack of moisture has left many forests and vegetation exceptionally dry. The driest vegetation in the Colorado-Utah-Wyoming region is in northwest Colorado and eastern Utah, according to the climate center. It also said models show very dry soils throughout western Colorado, eastern Utah and southern Wyoming, as well as in most of eastern Colorado.
Meanwhile, bark beetles have significantly expanded their range — and impacts — since 2002, a spread usually attributed to the same warmer temperatures and milder winters that happen to be behind this drought. This, combined with other factors including those same temperatures, lack of snowpack and dry vegetation, has already led to fires such as the Lower North Fork, Sunrise Mine and High Park. Powerful and frequent winds have also helped created a perfect environment for large blazes to start and grow.
At this time in 2002, though, the situation was even more dire, with a full seven fires ablaze on June 13 of that year versus two this year.
This year, the multiple fire bans already declared throughout the state are trying to douse flames before they start, Grand Valley water utilities are encouraging residents to self-impose restrictions on their water use, and low flows through the hydroelectric-powered pumps that bring irrigation water to Redlands has forced residents there to trade off watering days. It remains to be seen how far last year’s snowy bounty, stored in reservoirs, and whatever rains the summer may hold, will go toward ending these inconveniences and preventing bigger disasters.
“It’s getting pretty bad out there, and all we can do is ask for rain,” said Ryan, noting that it looks likely the La Nina episode that brought a wet winter last year and dry one this year may give way to an El Nino later this summer. If that does happen, she said, it should mean a wet winter.