Summer’s wet start a mixed blessing
By Joe Hanel 
| July 20, 2009 | 5:01 AM
The rainy weather this summer has been good news for botanists, who say it is a great year for wildflowers. (RMI photo by Werner Slocum)
The Rocky Mountain Independent is running a three-part series of environmental snapshots from the Front Range. Part one examines the forces that came together to produce the region’s wet spring and early summer, as well as the effects.
The Green Revolution has taken hold on the Front Range.
It’s got nothing to do with politics or environmental ethics, and everything to do with rain.
Although the recent onset of 90-degree days has put an end to the spell that was more like Seattle than Denver, the cool, wet spring and early summer was good news for botanists, foresters and water managers.
A lucky sequence of ocean currents brought the rain, said Klaus Wolter, a climatologist at the University of Colorado at Boulder.
“The best-case scenario that could happen for us in Colorado is we come out of a La Niña winter and switch to an El Niño in the summer,” Wolter said.
The La Niña current in the Pacific Ocean pushed heavy snow into the Colorado high country. Then, just as it was melting quickly, the El Niño current set in during the late spring, bringing rain and cool temperatures, he said.
The amount of rain wasn’t out of the ordinary, but the frequency was, Wolter said. June had a record 24 days of precipitation. All of that moisture kept temperatures low by absorbing the sun’s heat. Boulder didn’t reach 90 degrees until July 8 – the latest date since at least World War II, Wolter said.
Still, this year is nothing out of the ordinary from a historical perspective, he said.
And it’s hard to say whether this year’s weather has anything to do with climate change, he added. The computer models that predict global warming don’t rule out years like this, when the temperature is lower than normal.
But a wet spring sometimes can make for a scary fall fire season.
“In many ways, it’s a mixed blessing, depending on your perspective,” said Joe Duda, chief of the Colorado State Forest Service.
Spring rains lead to a buildup of grass and other “fine fuels” on the forest floor. If the rains don’t continue, the grass will dry out and turn into kindling.
But the fuel supply is only one of three components necessary for a forest fire, Duda said. A fire also needs hot, dry weather and an ignition source — both of which are impossible to predict.
The moisture this summer may have slightly slowed the advance of ips beetles, Duda said. But it won’t do anything to stop the mountain pine beetle, which recently advanced onto the Front Range after killing 1.5 million acres of lodgepole pines in north-central Colorado.
But Duda isn’t complaining about the weather.
“We’ll take it as it goes, but for right now, we like it,” he said.
Denver Water officials will take it, too. Water use is down 15 percent this year compared with the average from 2005 to 2008, Denver Water spokeswoman Stacy Chesney said. Compared with the 1993-2001 average, Denver customers are using 31 percent less water.
“They’re taking our efficiency messages and cues from the weather and watering less,” Chesney said.
Denver’s main reservoirs, including Cheesman, Dillon and Gross, had so much water that they spilled this spring, she said.
The department is continuing its water-conservation campaign, to keep the ethic alive for future years, which might not be so lush.
Botanists have had a good year, too. Jennifer Neale monitors rare plants on the Western Slope for the Denver Botanic Gardens. The late rains gave her a chance to collect seeds from imperiled plants — a chance she doesn’t get most years. Plant-monitoring teams on the eastern plains have reported a “phenomenal” year, Neale said. And hikers in the mountains can expect to see colorful meadows, she said.
“This year has been a really good year for wildflowers. It probably has a lot to do with the late rains we got this spring and early summer,” Neale said.
On the other hand, it’s been a difficult year for hikers above treeline. After a rapid snowmelt, cool temperatures froze the high-altitude snow in place, Wolter said.
“Once you got above 11,000 feet, it was hard hiking. It was difficult to get up high this year,” he said.
Now, with the monsoon season setting in, afternoon thunderstorms make it important for hikers to get off the peaks by noon. The monsoons should bring decent rains through August, Wolter said, but from here on, he expects “more of a garden-variety summer.”
Tomorrow: As the U.S. searches for new energy sources, nuclear power is back in the spotlight, and Colorado’s uranium deposits are, too.
climate, denver, El Niño, environment, green, La Niña, ocean currents, rain, reservoirs, spring, summer
