Some experts have believed that the first signs of California’s drought easing could emerge thousands of miles away in the Pacific Ocean near the equator.
That’s where the famously fickle weather condition known as El Niño forms. Predicting one can be difficult. But when the effects of a very strong El Niño arrive in California, heavy — sometimes epic — rains often follow.
Over the last year, scientists have been disappointed as signs of El Niño fizzled. But this week, they are seeing clear signals that the “great wet hope” is showing signs of life.
If the pattern forming in the Pacific does strengthen and persist, it could bring storms next winter that “would certainly provide what we would call genuine relief,” said climatologist Bill Patzert. “It could be ... potentially the beginning of the end of the drought.”
But it remains a big “if.”
Patzert said the increasingly warm temperatures in the Pacific Ocean along the equator this year were a reminder of conditions back in the spring of 1997, the prelude to a record El Niño year that brought heavy rains to California.
To California weather watchers, the winter of 1997-98 is significant because it brought widespread flooding and mudslides, causing more than half a billion dollars in damage and causing 17 deaths. Downtown L.A. got nearly a year’s worth of rain in the month of February.
“This looks like the real deal, and something that might replicate the famous 1997-98 El Niño. This is as close as we’ve come,” said Patzert, of the Jet Propulsion Laboratory in La Cañada Flintridge.
He and others are quick to warn that this El Niño could fade before the winter rainy season begins, which would do California little good.
“Should it become a strong event, that tilts the odds more in favor. But until it’s actually raining or snowing, nothing is actually guaranteed,” said Mike Halpert, deputy director of the National Oceanic and Atmospheric Administration’s Climate Prediction Center in Maryland. “It’s not quite time to buy the ark yet.”
On Thursday, El Niño was declared to be “weak-to-moderate” this month, stronger than its “weak” status in April, according to the Climate Prediction Center. The current El Niño was first identified in March.
The center said there was now an 80% or greater chance that El Niño conditions would persist through the latter part of the year — up from more than 60% in April’s forecast.
A strong El Niño that lasts deep into the winter and into next spring would be favorable in bringing much-needed rain to California. Very strong El Niños are very likely to bring substantial rainfall, much needed in a region besieged by years of drought.
There are a number of reasons to be optimistic for a strong El Niño this year, although last year the weather phenomenon failed to show up despite promising signs.
An ocean area roughly twice the size of the United States is warmer than normal in the Pacific along the equator, a situation similar to what occurred in 1997, Patzert said. Warm water is pushing eastward toward the Americas, because trade winds that normally push warm waters from the Americas to Asia have weakened.
“When you see that large of a redistribution of heat … it influences the Northern Hemisphere jet stream patterns,” Patzert said. “So that could — but not necessarily will — change the pattern that we’ve been stuck in, which is heat and drought in the West and punishing winters in the Midwest and Northeast.”
“Another way to say that: epic mudslides in California, with some drought relief thrown in, and golfing in Minnesota in February,” Patzert said.
Daniel Swain, climate scientist at Stanford University and author of the California Weather Blog, said scientists were observing changes in the atmosphere needed for El Niño to develop. Many scientific models of this El Niño are “suggesting, in fact, the potential for a really significant event.”
As temperatures continue
to rise, a weak to moderate
El Niño is established.
Warmer temperatures begin
to expand along the equator.
west of South America
(in degrees Celsius* above normal)
Rise in ocean temperatures
April 23, 2015
May 14, 2015
March 26, 2015
Lorena Elebee / @latimesgraphics
*1 degree change Celsius equals 1.8 degree
Source: National Oceanic and Atmospheric
El Niños are notoriously hard to predict. They can last nine to 12 months, and in some cases go for as long as 18 months. But they can also fizzle out with disappointing speed.
Traditionally, the models scientists use in the spring to foresee what will happen next winter are not that accurate. And Halpert said there’s concern that this El Niño will peak too early, although there are other observations that also show how it might not.
For all the uncertainty, more time will help.
“Hopefully in June, at the latest in July, we’ll have a better sense as to whether this is going to be at least a strong event,” Halpert said. “Then we’ll have to start trying to figure out predicting what type of winter you’ll have with the rain.”
But it would be a mistake to think of El Niño as a sudden fix to California’s drought problems.
It would take many years of rain to make up for existing deficits, and a single El Niño would not erase the problem of unsustainable demands on our water supply.
For all the hope for rain, the return of a very strong El Niño might soon be seen with regret if it brings severe damage to California, as in years past.
“Everyone is thinking of this in terms of drought relief. What they’re forgetting is if this thing really materialized, once this thing starts, the drought story will be secondary to the destruction story,” Patzert said. For more California breaking news, follow me on Twitter: @ronlin