El Nino …dream or nightmare?
The massive El Nino brewing in the Pacific Ocean could be a Tahoe skier’s wildest dream or worst nightmare.
Called the Christ Child (in Spanish) because it shows up in early December in the waters off Peru, El Nino warms the ocean surface and reacts with the atmosphere to dramatically change weather patterns in various parts of the world.
For Truckee-Tahoe, that means there are no guarantees that residents should be tuning up their snowblowers and buying full season ski passes.
“There is not an absolute correlation between a strong El Nino and heavy snowfall in the Sierra Nevada,” said Randall Osterhuber, of the U.S. Forest Service’s Central Sierra Snow Lab.
This region could experience extreme drought or huge snowfall.
“It’s an unknown right now,” said National Weather Service meteorologist Roger Lamoni. “The odds are quite high it will be wet in Southern California, the southern states and Northern Mexico.”
It is expected to be drier than normal in British Columbia, Washington and Oregon, he noted.
But because Northern California and Northern Nevada are in the middle of the two extremes, the odds of a dry or wet El Nino year are about 50-50, Lamoni said.
Two large El Nino events of the past affected Tahoe-Truckee in opposite extremes. In 1976-77, Donner Summit only received 183 inches of snow for one of the driest years on record at the Norden snow lab, Osterhuber said. In 1981-82, the lab recorded a whopping 671 inches of snowfall, well above the average snowfall of 461 inches, Osterhuber said.
“They were both around an El Nino event,” Lamoni said.
During the 1976-77 water year, Lake Tahoe dropped below its rim in September and Lake Shasta in Northern California nearly dried up. In 1981-82, the snowfall was so heavy in Tahoe that residents were trapped in their homes for days and a huge avalanche at Alpine Meadows Ski Area took the lives of several employees.
Lamoni said that this year’s El Nino is expected to be stronger than either 1976-77 or 1981-82.
Mark McLaughlin, a Sierra weather historian, said that there have been between 25 and 30 El Nino events during this century. Aside from 1976-77 and 1981-82, other El Nino years were 1986 when the Sierra received 22 inches of rain in February, causing severe flooding in Northern California and Reno; 1969, which was a record winter in Tahoe; and 1924, one of the driest years on record.
McLaughlin said that there is a slightly better chance of a strong El Nino bringing Northern California wet weather, as opposed to dry weather.
However, he cautions that weather in general during the 1990s has been very bizarre, so anything could happen. The only sure factor is that El Nino is in the Pacific Ocean.
“We’re going back into another really serious El Nino with a vengeance. They disrupt typical weather patterns, but I haven’t seen a typical winter up here in many years,” McLaughlin said.
The jet stream will make the difference in a wet or dry year for Northern California, Lamoni said.
“It’s where the jet stream comes and hits the West Coast. It’s kind of like a fire hose,” Osterhuber said.
Lamoni said it is too early to tell how El Nino will affect the region, although meterologists can already track its current effects on weather patterns. The ocean temperatures already show the presence of El Nino, but the atmosphere hasn’t changed enough to track where El Nino’s effects will be this winter. As the days get shorter and the temperatures cool, then the jet stream will find its pattern for the winter.
“Even though the ocean is warm, the atmosphere is in a summer mode,” Lamoni said.
Took out of Vail story, you can use it as a sidebar if you want.
At the National Oceanic and Atmospheric Administration Climate Diagnostic Center in Boulder, data research scientist Klaus Wolter and his colleagues study detailed readings of relevant oceanic and atmospheric data.
Their readings begin thousands of miles away in the eastern half of the equatorial Pacific Ocean. Right now, the temperatures there are about 4 degrees Centigrade warmer than normal. And not only is it 4 degrees warmer, but it warmed that much in just two months – a shorter timespan than any other El Nino in history.
What a difference timing and a few degrees can make. Combined with air temperature, air pressure, water pressure, and winds, those 4 degrees have big implications for weather patterns across the globe.
“El Nino is a phenomenon that occurs between the ocean and the atmosphere, and it’s centered in the equatorial Pacific Ocean,” researcher Klaus Weickmann said.
“The ocean by itself or the atmosphere by itself wouldn’t be able to oscillate or change things. They influence each other,” he said.
This year’s El Nino is more intense than any other in history because it developed so rapidly and because the measurements deviate so drastically from average.
At no other time in 100 years of recordkeeping has the water warmed so quickly, Weickmann said.
– World News Service
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