A stormy future
Climatologists link extreme weather and global warming

Snow lines Main Avenue following last week’s series of epic snowstorms. More than 3 feet of the white stuff fell in what is being characterized as a classic El Niño event. Regardless of El Niño, violent storms are becoming more common in Colorado and all over the West. Several studies are linking the increase in extreme weather to global warming./Photo by Stephen Eginoire

by Will Sands

Giant storms are making more and more appearances on the local weather map. And though last week’s massive dump in Durango may have been a “classic El Niño” event, many links are emerging between global warming and a surge in extreme weather events in Colorado.

As Durangoans know, El Niño can be a fickle character. The phenomenon characterized by a warming in the equatorial Pacific Ocean does influence weather patterns in the Southwest United States. However, El Niño does not always show up and bless the Four Corners with abundant moisture. That said, the winter of 2009-10 is turning out to be a benchmark year for El Niño, according to Klaus Wolter, an atmospheric scientist with the University of Colorado at Boulder and the National Oceanic and Atmospheric Administration. Last week’s storm – which pounded Durango for five days and brought more than 3 feet of snow to downtown – was typical of the weather phenomenon.

“El Niño tends to favor the southwest part of our state with additional moisture,” Wolter said. “Not every El Niño delivers, but last week’s storm was classic El Niño.”

The current event is the strongest El Niño since the winter of 1997-98, the atmosheric scientist said, and “the boy” promises to linger in the Southwest for the remainder of the winter.

“El Niño is cranking this year, and this is the strongest event since 1997-98, which was really the benchmark,” Wolter said. “I also don’t expect it to die off or go away anytime soon. We typically expect a wet spring with El Niño.”

Wolter characterized last week’s storm as an extraordinary event – not record-breaking but likely among the top 10 biggest storms to hit the region in the last 50 years. The fact that it came on the heels of a large storm in early December is also significant, he said. “Extreme storm events seem to be getting more common in Colorado,” the scientist said, noting research into the last five decades of snowfall data. However, Wolter also said he is not ready to point any fingers or name any  causes. “You’re not going to get me to say it’s because of global warming,” he remarked. “The cause really is not as important as whether it’s getting wetter or drier in the region."

A classic Dodge van sits hood-deep in snow on E. Third Ave. last Friday./Photo by Stephen Eginoire

But many climatologists, watchdogs and officials are concerned about what’s behind the growing frequency of major storms. With global temperatures increasing by an average of 1.1 degrees Fahrenheit over the last century, major storm cycles are also on the rise. The phenomenon has been especially significant for Colorado, according to a 2007 report by the conservation group Environment Colorado. Violent storms in Colorado are up by 30 percent over only 60 years ago, according to “When it Rains, it Pours: Global Warming and the Rising Frequency of Extreme Precipitation in the United States.”

“At the rate we’re going, what was once the storm of the decade will soon seem like just another downpour,” said Keith Hay, energy advocate at Environment Colorado. For the report, analysts with Environment Colorado examined large rain and snow events through the continental United States between 1948 - 2006 and discovered a nationwide jump in extreme precipitation and pointed to a 25 percent increase in the frequency of extreme weather events in the Mountain West. In addition, Colorado boasted one of the top increases in the nation, clocking in at a 30 percent growth in severe storms during the nearly 60-year test period. Taking an even closer look, “When it Rains, it Pours” cited an even more dramatic jump in Colorado’s high-desert regions and noted that storms with heavy precipitation had increased by a staggering 53 percent in parts of Colorado’s Western Slope.

The National Aeronautics and Space Administration (NASA) reached similar conclusions with a new climate model that points to violent storms and tornadoes becoming more common as Earth’s temperatures warm. Researchers Tony Del Genio, Mao-Sung Yao and Jeff Jonas established a link between warmer temperatures and “severe thunderstorms” in particular. They also drew a conclusion that perfectly describes this year’s winter in Durango – a warmer climate is making for more severe weather events but fewer storms overall. Higher temperatures and increased storm activity also mean more violent rainstorms and fewer snow showers, a phenomenon Durango residents have experienced firsthand in recent years.

Environment Colorado argued that the findings point toward a need for solutions, and the group suggested that reversing global warming is the only “real” answer. Hay noted that an increase in extreme weather events does not necessarily mean more water will be available. Instead, scientists expect longer periods of dryness between the storms and increasing risks of protracted drought.

“How serious this problem gets is largely within our control,” Hay said, “but only if we act boldly to reduce the pollution that fuels global warming.”

Wolter, on the other hand, sees no danger of drought in the Durango forecast for 2010. Now that El Niño has grown into a “strong event,” the Southwest has its best chance in years for a wetter-than-normal winter, he said. And for those suffering from sore backs and tired shoveling arms, Wolter offered the reminder that much of the rest of Colorado is in the midst of a drought winter.

“The snowline is basically south of the main divide of the San Juan Mountains.,” he said. “I think you should consider yourselves blessed.”