What A Strengthening El Niño Means For Colorado
Climate forecasters say the possibility of a strong El Niño in 2015 could mean above average precipitation and an increased flood risk for Colorado.
The natural phenomenon arises from variations in ocean temperatures in the tropical Pacific, said University of Colorado, Boulder researcher Klaus Wolter.
"When we are in a situation like we have now with at least moderate El Niño conditions we do tend to get wetter summers." Although signs point to an El Niño, Wolter was still cautious.
"It is not a slam dunk, it is not guaranteed," he said. "I would say there is a like a 2-in-3 chance of having a wetter summer this year in Colorado, which is good news."
According to Wolter the El Niño is still in its early stages, but has the potential to cause extreme weather around the world. Researchers will have a clearer understanding in July after they collect more data on the strength of the storms.
Wolter is more confident about this prediction because scientists have more complete data from buoys in the tropical Pacific.
Colorado has seen false starts in El Niño-related weather. There were similar conditions and weather patterns in spring 2014, but the El Niño did not progress over the summer.
"Sometimes you get too much of a good thing."
"Yes there is a chance that this could be quite big, but having seen what happened in the last three years, there is still the chance that this thing could fizzle. Although I think the odds for that are much lower than before," Wolter said.
A strong El Niño will bring increased rain to drought stricken areas of the West like California and Nevada, though it won't be enough to get them out of the drought, Wolter cautions. The precipitation it typically brings could mean good news for Colorado's farmers, especially in the parched southwest region, as well as a possible decreased wildfire risk statewide.
Although an El Niño means more precipitation over the summer in Colorado, that doesn't translate to a snowy winter. In fact, it's often the opposite.
"Unfortunately that means a low snowpack. In mid-winter you typically just don't get much precipitation out of El Niño in Colorado," Wolter said.
The last El Niño was in 2009-10. Wolter classifies it as moderate.
The last strong El Niño - like what may happen in 2015 - was in 1997, and many Coloradans may remember it. In July of that year, flash flooding occurred in Fort Collins when 10-14 inches of rain fell over a 31-hour period. The flood resulted in five deaths and an estimated $200 million in damages, according to the City of Fort Collinswebsite.
With increased precipitation comes increased risk of flooding, according to Wolter.
"Sometimes you get too much of a good thing. If you look at historical cases where an El Niño got going, especially in the last 50 years, the Big Thompson flood in 1976, the Fort Collins flood in 1997, there was some really big floods in and around Denver in 1965, those were all El Niño summers," said Wolter.
But, Wolter cautions, not all floods are linked to El Niño.
"Remember, 2013 had terrible flooding and that wasn't [during] an El Niño," he said.