The storm systems that moved over the US since the 20th of December didn’t do much to alleviate drought conditions across the US, according to the Drought Monitor. As of Jan 1, 2013, 61% of the contiguous US is experiencing moderate or worse drought (D0-D4). The percentage area experiencing exceptional drought edged up slightly from 6.7% to 6.8%. Percentage areas experiencing drought across the West stayed mostly the same at the end of December as they were the 11th of December. Drought across the High Plains expanded slightly during the same period. Meanwhile, drought across the Southeast and Northeast improved somewhat. Midwest drought remained largely unchanged.
The snow that fell over the intermountain west will have to melt in the spring before conditions improve there. Additional help will have to come this summer via the monsoon before this wide expanse of severe drought is alleviated.
The snow that fell over these areas prior to Christmas didn’t help with drought conditions – yet. Above-average snow will also have to fall over the High Plains before conditions improve much. It was simply too hot and dry over these states last year for one storm to significantly impact drought conditions.
According to the US Climate Prediction Center’s Seasonal Outlook issued yesterday, little relief is likely through March 2013:
As this figure shows, the edges of the drought affecting the western 2/3 of the nation could see some improvement. Conditions over the southeast, which experienced drought for a couple of years, could also improve in the next three months.
I’ve been reading a large number of scientific papers on drought. While extensive and severe in absolute magnitude, the current drought isn’t worse than the droughts of the 20th century (1950s and 1930s). So far, enough precipitation has fallen in the right areas at the right times to alleviate severe impacts on societies. In contrast, 20th century droughts affected people quickly – largely because they were unprepared for the conditions they experienced. Those prior circumstances helped inform decision makers so that future effects would not be as severe as quickly. That said, people would not be adequately prepared if conditions revert back to those last seen in the 1100s. Multidecadal droughts have occurred over substantial parts of the US. The relative wetness of the 19th and 20th centuries are not likely to continue into the 21st, especially as global temperatures continue to rise. How will we prepare and respond?