La Niña brings flood risk, drought to the West
SALT LAKE CITY – The winter and early spring have been extreme across the West, with record snowpacks bringing joy to skiers and urban water managers but severe flood risks to northern Utah, Wyoming and Montana.
And despite all the wet weather in the Rockies and Sierra Nevada, parts of eastern Colorado, New Mexico and Arizona are in severe drought and gearing up for what is forecast to be a bad fire season. In New Mexico, some 400 fires, driven by relentless winds, have already raced across 315,000 acres.
Credit – or blame – for the extreme weather goes mostly to a strong La Niña, which is associated with cooler than normal water temperatures in the Equatorial Pacific Ocean and an atmospheric flow that’s causing drier than normal conditions in the Southwest and wetter than normal in the Northwest.
“This winter has been fairly unusual,” said Laura Edwards, a research climatologist at the Desert Research Institute in Reno, Nev., in what can only be considered an understatement.
Randy Julander, supervisor for the Utah Snow Survey, described more colorfully the disparity between the snow-buried, flood-endangered parts of the West and those that are parched and burning: “They’re wishing they could get a little of what we have. (The wet weather) just continues to get worse. At this point, all you can do is open the chute, let her buck and hope your butt stays glued to the saddle.”
Julander was referring to the coming melt with snowpacks at 200 percent of normal or higher throughout northern Utah. One lower-elevation area in the mountains 50 miles east of Salt Lake City is at 750 percent of normal – with another big storm headed to the region early this week.
In Colorado, the city of Denver and Loveland Ski Area are separated by a mere 75 miles. Yet the city, east of the Rockies on the high plains, has had only 21.8 inches of snow this season, the second-lowest in history with records dating back to 1882. Loveland, at the top of the Continental Divide, entered the weekend within four inches of breaking its season snowfall record of 572 inches (some 49 feet, set in 1995-’96).
“It’s almost a record low for one and a record high for another. You get the idea how extreme that is,” said Kevin Houck, an engineer with the Colorado Water Conservation Board. “If I were a water manager, I’d be very happy about this.”
Pat Mulroy definitely is.
She oversees operations at the Southern Nevada Water Authority and the Las Vegas Valley Water District, responsible for water to local agencies that collectively serve 2 million residents and nearly 40 million annual visitors.
As recently as last fall, the plunging levels of Lake Mead outside Las Vegas were dangerously close to triggering a mandated “shortage” declaration on the Colorado River system, which would have required both Nevada and Arizona to reduce water use.
But because so much snowmelt will be flowing into the Colorado River this year, the U.S. Bureau of Reclamation announced recently it is releasing an extra 3.3 million acre-feet from upstream Lake Powell to Lake Mead. The additional flow into Mead is roughly 14 times the amount of Colorado River water Las Vegas and surrounding areas used last year.