For months, local skiers were in a mood of gleeful anticipation with an El Niño year on the horizon, which might mean a heavier snow winter. Then we waited and waited.

Finally, on March 5, meteorologists at the National Oceanic and Atmospheric Administration announced that El Niño conditions had arrived – after winter was nearly over. What it means for Southwest Colorado is still uncertain, they say.

“We’ve been flirting with the threshold on and off almost since last spring,” said Colorado State Climatologist Nolan J. Doesken, who is based at the Colorado Climate Center at Colorado State University in Fort Collins. “Last spring, we got all excited and thought we might be ramping up to a very favorable winter, but it didn’t happen. Now, we’ve gently crossed the threshold.”

Specific conditions must exist to say we’re in an El Niño weather pattern. Ocean surface temperatures in a specific part of the equatorial tropical Pacific Ocean, west of Peru, must increase more than 0.5 of a degree Celsius, about 1 degree Fahrenheit. But it is what meteorologists call a coupled phenomenon, NOAA said, where the atmosphere in the area also has to warm up and conditions need to indicate that it will stay at those temperatures for the next several seasons.

“In the last six weeks, we’ve been starting to see some atmospheric response,” said Joe Ramey, a meteorologist with the Grand Junction office of the National Weather Service, who translates climate date into predictions for Western Colorado. “But different meteorologists have different definitions for what has to happen to be in El Niño conditions. The Japanese called it a month or two ago. What a spring El Niño will mean compared to a fall one is uncertain.”

What will happen here?

“If it keeps on, it’s a little more favorable for wet spring storms rather than dusty wind storms,” Doesken said.

Norv Larson, one of Ramey’s meteorologist colleagues in Grand Junction, is not sure we’ll see any extra moisture.

“When you look at El Niño predictions on the map, you see bulls-eyes on some areas, but we’re in the area in-between,” he said. “It may well be that there’s not more moisture than normal, and there’s not less moisture, either.”

In other words, the weather may be normal – a dry spring.

“Every El Niño has its own flavor,” said Ramey, who has been tracking El Niños since he was in college. In general, there’s been little impact to summer weather during an El Niño, he said, although it may mean an early start to the monsoon season.

‘One step closer to La Niña’

Some prognosticators are saying this may be a two-year El Niño.

“La Niña tends to be more likely to last longer,” Doesken said, “and El Niño tends to be shorter, but that’s not always the case. I’d be happy to have another year of El Niño.”

If it is the start of a curtailed El Niño, Doesken said, it may mean we’re “one step closer to La Niña conditions.”

La Niña tends to mean cooler, but drier, weather patterns.

“That’s when we really start worrying about drought in Southwest Colorado,” he said. “You haven’t really recovered from the drought of the last few years.”

What we do need to worry about is continuing warmer temperatures, Doesken said. La Plata County just finished a winter that was 5 degrees above normal over the three-month period from December through February.

“You’ve been on the warm side for several years, and I’m definitely concerned that temperatures will be on the hot side for the coming year,” he said. “You’re more likely to have the thermostat turned up and be very much warmer than average temperatures.”

abutler@durangoherald.com

What’s what

El Niño occurs when the water and atmospheric temperatures in the Pacific Ocean off Peru rise. In Southwest Colorado, it usually means unusually wet winters but has not traditionally affected spring and summer rains.

La Niña occurs when ocean and atmospheric temperatures in the same region cool and often follows El Niño conditions. In Southwest Colorado, that usually means unusually dry winters and may extend into drier than normal summers as well.

Monsoons in Southwest Colorado refer to afternoon rainstorms generally beginning by the second week of July and lasting at least until the end of August.

Drought conditions occur when a region receives significantly lower than normal amounts of precipitation over an extended period of time. The drought in Southwest Colorado has lasted about 14 years, the longest and most severe in centuries.