La Nina weather pattern unusual this year
December 14, 2011
EAGLE COUNTY – La Nina is supposedly back again this winter, but recent weather patterns have been dumping the most snow on the southern part of the state, which is more typical of an El Nino winter.
Weather forecasters say La Nina – a weather system where cold ocean temperatures in the eastern Pacific Ocean bring wetter than normal conditions across the Pacific Northwest and drier and warmer than normal conditions across much of the southern United States – is weaker than it was last winter. Recent weather patterns, however, just don’t follow any conventional wisdom about snow in northern Colorado, La Nina winter or otherwise.
Joel Gratz, a meteorologist who runs the website http://www.onthesnow.com, formerly http://www.coloradopowderforecast.com, calls the weather pattern we’ve seen over the last six or so weeks “pretty difficult.”
The computer forecasting models that Gratz and other weather forecasters use haven’t been helpful in predicting when the current pattern will shift. Gratz said it looked like the shift would come around Dec. 10, and then it looked more like Dec. 17, and now it looks more like Christmas, he said.
“I’ve lost confidence in when it will shift,” Gratz said, adding that he’s confident it will eventually shift.
The pattern is such that storms have been coming in from the Pacific Ocean over British Columbia, Washington or Oregon – as they typically do in La Nina winters – but then the systems have been splitting into two sections. The southern portion has been tracking farther south, while the northern portion stays north of Colorado, said Jim Daniels, a forecaster with the National Weather Service in Grand Junction.
The systems have just been going too far south to bring any significant snowfall to the Interstate 70 corridor. The next 14 days just show more of the same, too, Daniels said.
“The outlook for the weather service is still below normal precipitation,” Daniels said. “So not any significant change from what we’re seeing now.”
Gratz said it would have been impossible to predict this scenario in advance of the season, but now that it’s here, it’s becoming impossible to predict when it might change.
“The weather can usually get stuck in a rut, which can be good or bad,” Gratz said. “A lot of times, storms will follow the storm before them.”
Too early to worry
The news has been great for resorts like Wolf Creek, which has received significant snowfall accumulations over the last week and a half or so. And Vail and Beaver Creek have seen some light snowstorms move through in the same time frame, but accumulations have been minimal.
The U.S. Department of Agriculture’s Natural Resources Conservation Service snow measurement data shows Vail Mountain precipitation from Oct. 1 to Dec. 13 of this year at 72 percent of normal.
“The scenario, it’s unfortunate,” Gratz said of the recent weather patterns.
But it’s too early to worry too much about it, he said. Gratz has experience with forecasting Colorado snow, and he knows the pattern will eventually shift to some other pattern, which is “hopefully snowier.”
“The hope there is we stay in that (snowier) pattern for an equal amount of time (that the dry pattern has stuck around),” Gratz said.
Gratz said he’s amazed at how much terrain is open at both Vail and Beaver Creek based on recent weather patterns.
Vail Mountain spokeswoman Liz Biebl said the resort is trying to be “as aggressive as possible with snowmaking and our groomers are working very hard to put out a great product.”
“We will be adding terrain to the mix (today) with the Sourdough Express Lift (Chair 14) and Two Elk opening Wednesday. We’re continuing to look at other areas and will open as much terrain as possible on the front side as soon as we are able,” Biebl said via email. “Conditions are still looking good for snowmaking. Snowmaking still only covers a relatively small percentage of our overall terrain, so we’ll see how Mother Nature treats us and continue to assess conditions and the need for snowmaking at the end of the year and into 2012.”
Cold temperatures in recent weeks have made for great snowmaking conditions. Both Vail and Beaver Creek have been firing up their snow guns around the clock to get a solid base depth in place in time for the busier holiday season. Vail and Beaver Creek are both reporting an 18-inch mid-mountain base depth.
“Beaver Creek is still making snow in areas where we plan to open additional lifts and terrain for this weekend and beyond. We also are making snow on our tubing hill in time for the holiday period,” said Beaver Creek Resort spokeswoman Jen Brown. “The recent cold temperatures over the past two weeks have allowed our crews to be very productive and we’re beginning to wind down our snowmaking operations.”
The resorts are ready for slow starts to the winter – it’s why Vail Resorts has invested millions into its snowmaking infrastructure. And locals who have lived in the valley long enough know a slow start to winter doesn’t necessarily foreshadow what’s to come.
“The snow will come, it always does,” said Matt Jones, of Eagle, via the Vail Daily Facebook fan page. “By the end of the year, we’ll have 300 to 350 inches, so says the law of averages. The pattern is stuck, however, and long term forecasts don’t look great for a pattern change through the month of December.”
Gratz said it’s too early to start giving up on winter, too. People who talk about the current conditions as if it’s a “winter-killer” are off base, he said.
“It’s way too early to talk about this kind of stuff,” Gratz said. “You can get a month of really good snowfall. … We kind of got spoiled last year.”
But with La Nina still hanging tight this winter, the odds are still that Vail and Beaver Creek will see plenty of snow, and potentially more snow than average, Gratz said.
“It’s never a guarantee, but the odds are in your favor,” he said.
Community Editor Lauren Glendenning can be reached at 970-748-2983 or firstname.lastname@example.org.