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GTG
Was lost but now am found
Joined: 30 Dec 2002
Posts: 2387
Location: Peoria, Arizona, originally from Rocket City, USA
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 Posted: 11/8/2005, 10:25 am Post subject: Will this winter bust drought? |
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From today's Arizona Republic -
http://www.azcentral.com/news/articles/1108winter.html
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Will this winter bust drought? Not even scientists know
Last year was good start, but long dry spell is possible, too
Shaun McKinnon
The Arizona Republic
Nov. 8, 2005 12:00 AM
Is this the winter that ends it?
A healthy dose of mountain snow put a deep dent in the decadelong drought last year, and now, water and climate experts say they'll watch the coming months closely for signs that weather patterns have taken a turn back toward normal.
The hitch is, the more they learn about what controls the weather, the less certain they are about what normal is.
But figuring it out is critical. Water managers in Arizona and across the West are struggling to produce resource plans for the coming years, more aware than ever of how seriously drought can affect the growing region. They'd like to say a good winter means the end of the drought, but they know better.
"We need to consider that last winter was a wonderful bonus year for us, a gift from God or nature, and then we have to take it in stride and use it to the best of our ability because it could go right back to being dry," said Charlie Ester, water operations manager for Salt River Project.
SRP water planners, like most of their colleagues in the arid West, look at every new year as the potential start of a drought. What has changed is that, until recently, they planned for a seven-year drought.
"Now, we're looking at it from a longer time frame," Ester said, "like 10 years, maybe."
Too hard to predict
The basic long-range forecast for this winter, the one produced by the federal Climate Prediction Center, isn't offering much guidance.
For the early months, November through January, the forecast calls for a better-than-average chance of dry conditions over most of Arizona. From January through March, which are the months when the most snow falls in Arizona's high country, the prediction center punts, saying there is an equal chance for wet, dry or normal conditions.
Across the Rocky Mountains, on the headwaters of the Colorado River, the center sticks with equal chances for any of the three outcomes for the entire winter.
"This is an important winter," said Kelly Redmond, regional climatologist at the Desert Research Institute in Reno. "We bought a little bit of time last year, but a lot of the water managers are wondering if it was just a good year in the middle of a run of bad years."
Last winter filled SRP's six reservoirs to overflowing, to the point that the water provider released billions of gallons down the Salt River after a series of wet storms. Runoff into the Colorado River was 105 percent of the long-term average, which seemed miraculous after five straight dry years.
"But I don't know if I'd hang my hat on this being another year like that," Redmond said. "We're still not sure where that winter came from. I've been talking to colleagues, and there really isn't a very good explanation for what was behind last winter."
Most of the rain and snow fell in two to three months, which produced impressive numbers on the bottom line.
SRP was nearly at capacity before the typical runoff season ended. The Colorado River recovered and pushed water levels up 31 feet at Lake Powell, which had dropped below the one-third-full line.
No knockout punch
But behind the totals, there were signs the winter didn't deliver a knockout punch to end the drought.
Although runoff from the Colorado River was above normal through June, which marks the end of the heaviest flows, the river has run below normal since then, dipping below 70 percent of normal in September.
Much of the higher flows actually came from the San Juan River out of New Mexico. The upper Colorado and the Green rivers were running slightly below normal most of the spring, a sign that the winter perhaps wasn't a regional drought-buster, hydrologists said.
"While the severity of drought conditions has eased, it's premature to declare that the drought in the Upper Colorado River Basin is over," said Tom Ryan, lead hydrologist for the U.S. Bureau of Reclamation in Salt Lake City.
In Arizona, precipitation has been at or below normal since spring.
The monsoon hit the state like a stone skipping across a lake, producing heavy rain in some areas and leaving others nearly dry.
Some of the answers about the West's weather may be found in the oceans.
Climate experts have long watched the Pacific for clues about weather changes, making famous the twin seasonal indicators El Niņo and La Niņa. But Ester said that although La Niņa was a fairly reliable pointer to dry conditions in Arizona, El Niņo was harder to pin down. Sometimes it brings wetter conditions but not always.
"Something else was overriding it," he said.
Far-away influence
Scientists now believe that weather here can be influenced just as easily by currents in the Atlantic or even the Indian Ocean, half a globe away.
"The reasons why the oceans are such a good predictor is that they have so much volume and momentum," Ester said. "They don't change quickly. All these things are tied together. You just have to unravel the mystery and find out where the actual connection is."
So the answer is?
"The answer resides in the oceans," Redmond said. "Whether conditions have changed all that much is still an open question right now. The odds are not too much positive or negative."
A wet winter under normal conditions would produce a healthy runoff in Arizona, Ester said.
Last year's storms helped saturate the ground and improve forest and rangeland health, which means more water should flow into rivers and reservoirs.
The next question is whether normal conditions are changing.
The climate-prediction center is forecasting higher-than-normal temperatures this winter across much of the Intermountain West, which has been the trend for several years, Redmond said.
Warmer winters spell trouble for water managers. They mean more rain than snow in some areas, which reduces the amount of runoff that reservoirs can capture. Warmer winters also start the melting season too early and drive up demand from water users.
Several new studies have noted the shifting conditions and say runoff seasons are growing shorter.
The effect is similar to reducing rain and snow totals, Redmond said.
"You lose a little bit every year, and it adds up. It's a systematic removal of a certain part of the water supply."
The good news is that last winter bought at least a year for users on both the SRP and Colorado River systems, which together provide more than two-thirds of the Valley's water supply.
"We watch every winter, of course," Ester said. "But if we could have a normal or slightly above-normal year, it certainly might bode well for the drought lessening its grip."
Reach the reporter at shaun.mckinnon@arizonarepublic.com or (602) 444-8632.
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Here's to a wet winter,
GTG
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Daddee
I once was a slug.
Joined: 04 Jan 2003
Posts: 2815
Location: Mesa, AZ
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| Posted: 11/8/2005, 11:54 am Post subject: |
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Indeed.
And not only for drought relief reasons either. Two wet winters in a row after so long a dry spell would mean that next spring's flower display will be something to behold.
_________________
"Only small minds want always to be right."
- Louis XIV
"...haven't you lived long enough to know that two men may honestly differ about a question and both be right?"
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Tom Treks
Gear Addict
Joined: 12 Jan 2003
Posts: 3347
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| Posted: 11/8/2005, 6:19 pm Post subject: |
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| It is a "double-edged sword" though. That could mean the possibility of an even nastier wildfire season next summer. There have been a number of trail areas that got scorched before I could see them in their splendor. Major bummer. |
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Davis2001R6
Joined: 12 Dec 2003
Posts: 5591
Location: Italy
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| Posted: 11/8/2005, 6:52 pm Post subject: |
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Good point, the Forest Road out to 4 Peaks got hit prettt good, all the cactus were burned up for a few miles of it. Lots of dead Prickly Pear and Saguaros 
TIM |
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Shawn
I'll sell you map to Lost Dutchman mine!
Joined: 03 Jan 2003
Posts: 2592
Location: Ahwatukee, AZ
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| Posted: 11/8/2005, 8:22 pm Post subject: |
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We would be needing rain starting pretty soon to make flowers next spring.
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The bear went over the mountain to see what he could see. |
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ghoster
Joined: 14 Nov 2003
Posts: 152
Location: Scottsdale
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| Posted: 11/10/2005, 11:30 am Post subject: |
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| Not to mention the washing away of trails and roads that happened last year. But it did make for some surprising water sources last year, which was nice. |
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