News•January 17, 2013

Drought Shrinks Slightly; NOAA Issues Gloomy Outlook

By Andrew Freedman & Dan Yawitz

The national drought footprint shrank slightly this week, as heavy rains fell across the South, Southeast, Midwest and parts of the Mid-Atlantic states, and major snowfall blanketed parts of the Rocky Mountains and Northern Cascades, bringing relief to those regions. However, the hardest-hit drought region — the Great Plains — continued to experience drier-than-average conditions, with the drought continuing to hold on.

A new federal drought outlook issued on Thursday projects that the drought conditions are likely to remain entrenched through April, and that the drought may even worsen from the Plains to the Rockies and into the Southwest, along with another area of persistent and expanding drought in the Southeast, including southern Georgia and the Florida Panhandle.

Rainfall during the past two weeks, showing the rains that fell from Texas through the Lower Mississippi River Valley, but lack of precipitation across the Plains.
Click to enlarge the image. Credit: NOAA.

“Unfortunately it looks like most of the central and southern Plains . . . is going to continue to have significant drought problems,” said Anthony Artusa, a seasonal forecaster with the National Oceanic and Atmospheric Administration (NOAA).

The economic impacts of this drought have been staggering. The drought of 2011-12, which is still ongoing, is comparable in size to severe droughts that occurred in the 1950s, and is already being blamed for more than $35 billion in crop losses alone, according to the reinsurance company Aon Benfield. Others estimate that the total cost could exceed $100 billion, making this event rival Hurricane Sandy for the most expensive natural disaster of 2012.

In Texas, which has been struggling with severe drought conditions since 2011, the areas of the state that recently emerged from drought are expected to slip right back into it during the latter half of the winter season and into spring, NOAA said.

As of Jan. 15, 58.87 percent of the land area in the lower 48 states was experiencing some form of drought conditions, according to the U.S. Drought Monitor. That marks a slight improvement from last week, when the number was 60.26 percent. More than half of the continental U.S. has been under at least moderate drought conditions since June. The drought peaked in July, when nearly 62 percent of the lower 48 states were classified as being in moderate drought or worse conditions.

According to climate scientists, the drought was most likely initially set into motion by the pattern of water temperatures in the Pacific and Atlantic Oceans, which can alter weather patterns, but manmade global warming may then have amplified the drought event by leading to multiple extreme heat events during the spring and summer of 2012. These heat events accelerated the development and intensification of the drought.

A recently released draft federal climate assessment shows that as the climate continues to warm in the next few decades, drought events are likely to become more frequent and severe, with more significant water supply and agricultural impacts in parts of the U.S.

NOAA's Seasonal Drought Outlook for Jan. 17 through April 30, 2013.
Click to enlarge the image. Credit: NOAA.

Kentucky saw the greatest turnaround this week, as the percentage of the state under no drought grew to 91.55 percent — up from 73.29 percent — returning the state to drought levels last seen in March 2012. Improvements were also pronounced in the South, where rain fell in Arkansas, Louisiana, and Texas.

Areas of the High Plains, though, saw conditions deteriorate yet again, as soil moisture remains extremely low heading into the second half of the winter and then the spring growing season. This could result in below-average precipitation and above-average temperatures across the Plains during the spring as the atmosphere responds to the dry surface conditions, a self-perpetuating drought feedback, Artusa said.

The percentage of land area under severe drought or worse in Colorado, Kansas, Nebraska, Wyoming and the Dakotas grew slightly this week, from 86.20 percent to 87.25 percent. A similar expansion was observed in Georgia, where the area of the state under moderate drought conditions or worse expanded from 87.21 percent to 91.24 percent.

A long period of below-average precipitation has led to exceptionally low water levels on the Mississippi River, which may force authorities to close the river to shipping traffic, something that would have major economic consequences. On Thursday morning, the water level on the river near St. Louis was 1.95 feet below average, and is forecasted to come within striking distance of the record low — 6.2 feet below average — set in 1940. The Army Corps of Engineers has been dredging sediment and removing large rocks from the riverbed to ensure that the commercial waterway stays open to barge traffic, but it’s not clear if that will succeed if precipitation remains below average in areas upstream.

NOAA’s drought outlook does offer some hope that beneficial precipitiation will fall in the Upper Mississippi River Valley and the Upper Midwest, areas that are currently along the outskirts of the drought region, including states such as Minnesota, Illinois, Iowa and Wisconsin. In the Southeast, some drought improvement is projected for northeastern Georgia through Southern Virginia.