The Northwest looks at a soggy summer, while the Southwest may just burn
In the good old days, Westerners only had to look at the mountains to get an idea of what the summer held in store for them. The deeper the snowpack, the better the water supply.
Lately we've been looking to the Pacific Ocean for the weather forecast. First there was El Nino, portending a dry, calm Northwest and a stormy, wet Southwest. Then came its capricious sister, La Nina, signaling scant precipitation except in the volatile Northwest.
"The Pacific is the 8,000-pound gorilla of the earth's climate," Frank Casey at NASA's Jet Propulsion Laboratory in Pasadena, Calif., told the Telluride Watch. "When it moves, we have to sit up and listen."
And now there's the Pacific Decadal Oscillation - or PDO in weather-speak. Meteorologists are just beginning to understand this large-scale weather phenomenon, which shifts periodically to produce El Nino- or La Nina-dominated decades.
The Pacific started moving into a La Nina-dominated PDO in mid-1998, says Bill Patzert of the Jet Propulsion Laboratory, creating "a large disturbance in the Force." What does this mean for the West? If meteorologists are correct, the Northwest will continue to be wetter and the Southwest may just dry up and blow away.
Neck deep in the NorthwestWinter got off to a slow start in some parts of the Northwest, but overall, winter storms surged like salmon returning to their spawning grounds. Eastern Oregon fishermen were coming up empty-handed until January, when precipitation averaged out, swelling rivers, and the Wallowa County Chieftain cheerily reported that "about everybody hooked one."
By the end of March, snowpack was 30 percent above normal in western Washington.
"For the Northwest, snowpack is white gold," says Patrick Mazza in the Whatcom Watch, because it means a good water supply for cities, more power for electricity customers, and river flows adequate to protect spawning fish.
To the south, the 400-mile-long Sierra Nevada Range coasted through its fifth winter of above-normal snowpack. This is good news for California and Nevada residents - Sierra Nevada runoff sustains 34 million people in those two states, 17 million alone in Los Angeles. Planners are not worried that the wetter-than-average winter will cause floods, since thus far it's been a cool spring, allowing the snowpack to melt slowly and evenly.
Rockies get mixed bagSpring isn't taking its time in the Rockies. Scientists at the Rocky Mountain Biological Laboratory near Crested Butte, Colo., say that the last two warm winters baffled some wildlife. Marmots are exiting hibernation early, and robins are reaching summer breeding grounds far ahead of schedule.
The early spring was heralded by a late winter, which had Colorado ski resorts panicking. It rained in January in Aspen, and Telluride reported a 33 percent drop in skier visits from October through December. In the Northern Rockies, a late February storm dumped 41 inches of snow in one day on Grand Targhee Ski Resort on the Wyoming/Idaho border, but Wyoming's snowpack remained below average all winter.
Some areas in northwest Montana and northern Idaho finished off the winter with above-average snowpack, but much of the Northern Rockies stayed alarmingly dry. Warm spring temperatures are melting snow faster than usual, and an early greening of forage lured bison out of Yellowstone National Park and across the Montana border. State officials promptly herded them back.
On April 16, the Montana Agricultural Statistics Service rated 50 percent of the topsoil statewide short of moisture, and the Farm Service Agency is considering making loans to ranchers for supplemental water. A lower-than-normal precipitation forecast for the summer doesn't help.
"It looks like it's going to be pretty gloomy," says Peggy Stringer in the Montana statistics office.
Southwest braces for droughtIn the Southwest, the warm, dry winter has officials bracing for a mean fire season (see story page 2). By mid-March, 187,289 acres in New Mexico had burned, three times the amount in all of 1999. On April 10, a 200-acre brush fire south of Albuquerque leaped the Rio Grande before it was contained. Eight days later, the New Mexico forestry division reported 10 fires in two hours. The high vegetation growth of the last 20 relatively wet years is fast becoming a tinderbox, says New Mexico fire information officer Terri Wildermouth. "Unless we get a lot of spring moisture, it could get a little hairy."
Southwest ranchers are also looking hopefully to the sky. Bluewater Lake, near Gallup, N.M., will not provide any irrigation water this year. Snowpack and streamflow projections are less than 70 percent of average in Arizona and New Mexico. The New Mexico Farm Bureau is considering cloud seeding - injecting clouds with chemicals to produce rain - to alleviate the dire situation.
At the Otowi Gauge east of Los Alamos, the Rio Grande spring runoff is expected to be just 45 percent of average. Some parts of the river might run dry this summer, threatening the endangered silvery minnow with extinction (HCN, 10/11/99: A tiny fish cracks New Mexico's water establishment). To prevent this, environmental groups have asked a federal judge to order Rio Grande managers to keep water in the river.
"The Fourth of July monsoon is our only hope," says Kelly Redmond of the Western Regional Climate Center.