domingo, 24 de febrero de 2013

Primavera seca

Una nota del New York Times de hoy da cuenta de las pobres perspectivas de humedad para el medio-oeste estadounidense en la primavera boreal que se aproxima. Ya hemos hablado de esto en ocasiones anteriores; esta nota confirma la tendencia que veníamos anticipando. Multitud de modelos climáticos basados en datos objetivos del calentamiento global coincidían en un aumento de la frecuencia de sequías en esta parte de América.

Título: Thin Snowpack in West Signals Summer of Drought
por Matthew Staver


DENVER — After enduring last summer’s destructive drought, farmers, ranchers and officials across the parched Western states had hoped that plentiful winter snows would replenish the ground and refill their rivers, breaking the grip of one of the worst dry spells in American history. No such luck.


Lakes are half full and mountain snows are thin, omens of another summer of drought and wildfire. Complicating matters, many of the worst-hit states have even less water on hand than a year ago, raising the specter of shortages and rationing that could inflict another year of losses on struggling farms.


Reservoir levels have fallen sharply in Arizona, Colorado, New Mexico and Nevada. The soil is drier than normal. And while a few recent snowstorms have cheered skiers, the snowpack is so thin in parts of Colorado that the government has declared an “extreme drought” around the ski havens of Vail and Aspen.
“We’re worse off than we were a year ago,” said Brian Fuchs, a climatologist at the National Drought Mitigation Center.


This week’s blizzard brought a measure of relief to the Plains when it dumped more than a foot of snow. But it did not change the basic calculus for forecasters and officials in the drought-scarred West. Ranchers are straining to find hay — it is scarce and expensive — to feed cattle. And farmers are fretting about whether they will have enough water to irrigate their fields.


“It’s approaching a critical situation,” said Mike Hungenberg, who grows carrots and cabbage on a 3,000-acre farm in Northern Colorado. There is so little water available this year, he said, that he may scale back his planting by a third, and sow less thirsty crops, like beans.


“A year ago we went into the spring season with most of the reservoirs full,” Mr. Hungenberg said. “This year, you’re going in with basically everything empty.”


National and state forecasters — some of whom now end phone calls by saying, “Pray for snow” — do have some hope. An especially wet springtime could still spare the Western plains and mountains and prime the soil for planting. But forecasts are murky: They predict warmer weather and less precipitation across the West over the next three months but say the Midwest could see more rain than usual.
Water experts get more nervous with each passing day.


“We’re running out of time,” said Andy Pineda of the Northern Colorado Water Conservancy District. “We only have a month or two, and we are so far behind it’s going to take storms of epic amounts just to get us back to what we would think of as normal.”


Parts of Montana, the Pacific Northwest and Utah have benefited from a snowy winter. But across Colorado, the snowpack was just 72 percent of average as of Feb. 1, which means less water to dampen hillsides and mountains vulnerable to fire, less water for farms to use on early season crops, and less to fill lakes and reservoirs that ultimately trickle down into millions of toilets, taps and swimming pools across the state.


Heavy rains and snow have recently brought some hope to the parched states of Iowa, Minnesota and Missouri, where the drought is easing. But 55.8 percent of the United States remains locked in drought, according to the government’s latest assessments. And states like Nebraska and Oklahoma are facing precipitation deficits of as much as 16 inches.


Without damp soil, many wheat crops will have trouble growing come March and April when they should be in full bloom, and corn and soybeans could be stunted after they are planted this spring. In a year when farmers are planning another record planting, some might be forced to sow fewer seeds because there is not enough soil moisture to go around.


In southwestern Kansas, Gary Millershaski said the wheat on his 3,000 acres was as dry as it had ever been after two years of drought. But as snow fell around him, he was smiling, a guarded optimist for this year’s planting. “If we get above average rainfall from here on, we’re going to raise a wheat crop,” he said. “But what are the odds of that?”


Senator Mark Udall, Democrat of Colorado, put it this way: “Mother Nature is testing us.”
But Washington is also posing a challenge.


Mr. Udall, Senator Michael Bennet, a Democrat, and other members of Colorado’s Congressional delegation are seeking $20 million in emergency funds to help restore watersheds in Colorado ravaged by last year’s wildfires. So far, there has been little action on the measure. Western politicians are also urging the Forest Service to move more quickly to modernize the shrinking and aging fleet of tanker planes it uses to douse wildfires.


If Congress does not head off the looming across-the-board budget cuts set to take effect March 1, financing for the Forest Service’s Wildland Fire Management program will be cut by $134 million. As many as 200,000 acres — an area about the size of Kansas City, Mo. — would not be treated to remove dry brush, dead wood and other tinder for wildfires.


In dry states like Colorado, officials are already preparing for the worst. Wildfires did $538 million in damage last year, burning hundreds of homes and driving away summer tourists. As late as December, when the high country should be blanketed by snow, a 4,000-acre fire continued to burn in Rocky Mountain National Park. To some officials, it was a harbinger of longer, fiercer fire seasons that may come with climate change. “It’s just so dry here,” said Tom Grady, the emergency manager in Aspen and the surrounding county, which is already meeting to fine-tune its fire plans for the summer.


Denver Water, which serves 1.3 million people, depleted many of its reservoirs after last year’s dry winter and an unrelenting spree of 90- and 100-degree summer days. Those basins never fully recovered, and are now an average of 63 percent full. The agency has already idled one water treatment plant to conserve its reservoir supplies, and officials say they are likely to declare a Stage 2 drought, limiting when people can water their lawns.


In Northern Colorado, a combination of drought and wildfire is shutting off the spigot for scores of farmers. Cities are worried about ash and sediment flowing from the burn areas into the rivers that supply their water, so they are holding onto every drop possible this year and not selling any water to local farmers.


In 2011, the Northern Colorado city of Greeley alone leased enough water to irrigate 13,000 acres of farmland — representing millions of dollars in wages for farmhands, seed money, fertilizer sales and profits for farmers. Every year, just after midnight on Jan. 1, farmers start calling the city to sign up to lease the surplus water. This year, Greeley had to call them all back to say there was none to be had.


Eldon Ackerman, who grows sugar beets, pinto beans and alfalfa on his farm in Wellington, said he had water supplies for only about one-third of his fields. He was praying the spring snow and rains would come to save him. If they do not, he said he might have to let 1,000 acres lie fallow this year.


“There isn’t any more water to get,” Mr. Ackerman said.

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