News•February 28, 2013

Heavy Rains, Snow Bring First Hint of Good Drought News

For the first time in many months, the update to the U.S. Drought Monitor brought encouraging news, after heavy rains caused the severe drought to drastically loosen its grip on the Southeast, while back-to-back blizzards allowed for modest drought improvement in the Southern Plains as well.

Precipitation during the past seven days across the lower 48 states. Note the heavy rains that fell in the Southeast.
Click on the image to enlarge. Credit: NOAA/NWS.

However, the drought — which in some respects is the worst such event to strike the U.S. since the 1950s — has clearly consolidated its hold on the West, with forecasts offering little chance of lasting relief, according to the new U.S. Drought Monitor and weather outlooks released on Thursday.

First, the positive news: There was a net decline in all categories of drought across the lower 48 states during the week ending on Feb. 26. Most of the drought relief was confined to the Southeast and Southern Plains. In the Southeast, the total area in moderate drought or worse plummeted to 27.26 percent from 43.76 in just one week.

The Feb. 26 Drought Monitor marks the first time since early July 2012 that less than two-thirds of the U.S. cattle inventory is in a drought-affected area, according to Brad Rippey, a meteorologist at the Agriculture Department. At its peak intensity last summer, the drought forced a sell off and relocation of herds of cattle, as ranchers in drought-affected areas could not afford to feed and maintain their herds.

Also, for the first time since August 2010, there is no area under “extreme” drought or worse in the Southeast, as a wet weather pattern in February paid off in the form of drought relief. The state of Georgia was free of extreme to exceptional drought for the first time since May of 2011. Columbus, Ga., and Charleston, S.C., both recorded their wettest February on record, with more than a foot of rain falling at both locations.

There is still an area of moderate to severe drought stretching from the southern tip of Florida to southern North Carolina, but the dry conditions that have gripped Georgia for three years appear to be fading.

The weather pattern over the next week favors at least one more significant storm in the Southeast or Mid-Atlantic states, which could put another dent in the region’s long-term rainfall deficit.

The drought also improved in the Southern Plains, as two severe winter storms brought wind-whipped snows to the parched Texas Panhandle, parts of Oklahoma, and Kansas. Wichita, Kan., picked up 21 inches of snow in February, a monthly record. In Amarillo, Texas, the 19 inches of snow that fell on Feb. 25 was the second-biggest snowstorm on record there, just shy of the all-time record of 19.3 inches.

When the snow melts it will convert to about 1 to 2 inches of water, according to National Weather Service (NWS) estimates, which will help alleviate the extreme to exceptional drought conditions in the southern Plains.

Texas blizzard video by the National Weather Service.

However, very little drought improvement was seen in the central and northern Plains, where exceptional drought — the worst category — remains widespread. And in much of Texas outside of the sparsely populated Panhandle region, drought conditions worsened in the past week, leading to an overall mixed picture in the Lone Star State.

The drought, which enveloped a majority of the lower 48 states in 2012, was most likely initially set into motion by the cooler-than-average water temperatures in the tropical Pacific Ocean, combined with the effects of warmer-than-average waters in the Atlantic Ocean, a setup that studies have shown to be especially favorable for U.S. droughts.

But some scientists have shown that the overall warmer climate created by manmade global warming may have amplified this already devastating drought, particularly by triggering more intense heat during the spring and summer of 2012.

A new federal climate change assessment shows that as the climate continues to warm in the next few decades, drought events are likely to become more frequent and severe, leading to more significant water supply and agricultural impacts in much of the U.S

The West Is Locked In

The news for the West, however, was not as positive as drought continues to expand and deepen, threatening to yield another summer of water shortages and wildfires.

Total precipitation forecast for the next seven days, ending on March 6. Note the lack of rain or snow in the West, with the exception of the Pacific Northwest.
Credit: NOAA/NWS.

“The West had a great start to the snow season in December and January but since then it’s completely shut off,” said Brian Fuchs, a climatologist at the National Drought Mitigation Center, based at the University of Nebraska-Lincoln. Drought intensified in New Mexico and California, with all of California being classified as abnormally dry or worse. According to the Drought Monitor, groundwater issues are becoming a larger concern in California, and dry soils and thin mountain snows are a worry there as well as in New Mexico.

The Sacramento Bee reported that the northern Sierra Nevada mountains are likely to break an all-time record for the driest January-through-February period. That brings major concerns since the winter snowpack in the region helps fill California’s largest reservoirs, providing water to tens of millions of people throughout the dry spring and summer months.

Napa County, Calif., has received just 0.62 inches of rain during the January and February, its driest such period on record, and about 8 inches below average, according to NWS data.

Weather forecasts for the next two weeks show little chance of enough precipitation to alleviate the widespread drought across the West.