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51.4% of the Contiguous United States in Moderate or Worse Drought – 12 Mar 2013


According to the Drought Monitor, drought conditions improved recently across some of the US. As of Mar. 12, 2013, 51.4% of the contiguous US is experiencing moderate or worse drought (D1-D4).  That is the lowest percentage in a number of months. The percentage area experiencing extreme to exceptional drought increased from 17.7% to 16.5% in the last month. Percentage areas experiencing drought across the West stayed mostly the same while snowpack generally increased. Drought across the Southwest decreased slightly and rain from storms improved drought conditions in the Southeast.

My previous post preceded a major winter storm that affected much of the US.  In some places in the High Plains and Midwest, 12″ or more of snow fell.  With relatively high liquid water equivalency, this snow represented ~1″ of water precipitation.  Unfortunately, these same areas required 2-4″ of rain to break their long-term drought.  In other words, while welcome, recent snows have not substantially reduced drought severity affecting the middle of the nation, as the following map shows.

 photo USDrought20130312_zps72bb93c6.gif

Figure 1US Drought Monitor map of drought conditions as of the 12th of March.

If we focus in on the West, we can see recent shifts in drought categories:

 photo west_drought_monitor_20130312_zps8abffb70.png

Figure 2 – US Drought Monitor map of drought conditions in Western US as of the 12th of March.

Some small relief is evident in the past couple of weeks, including some changes in the mountains as storms recently dumped snow across the region.  Mountainous areas and river basins will have to wait until spring for snowmelt to significantly alleviate drought conditions.  As you can probably tell, this is a large area experiencing abnormally dry conditions for almost a year now.

Here are conditions for Colorado:

 photo CO_drought_monitor_20130312_zps0a6b5cbd.png

Figure 3 – US Drought Monitor map of drought conditions in Colorado as of the 12th of March.

Drought conditions improved somewhat across the southwestern portion of the state in the past couple of weeks.  The percentage area that is experiencing less than Severe drought conditions continues to track downward, which is a good sign.  Unfortunately, Exceptional drought conditions continued their hold over the eastern plains.

Here are conditions for the High Plains states:

 photo high_plains_drought_monitor_20130312_zpsa5bbbbdc.png

Figure 4 – US Drought Monitor map of drought conditions in the High Plains as of the 12th of March.

Again, even with large snowfalls in the past month, little drought relief is evident across this region.  What these states need are frequent soaking rains in the spring and summer to alleviate their long-term drought.  Agriculture certainly could use that relief this year.

And finally the area that experienced the most relief in the past month, the Southeast:

 photo southeast_drought_monitor_20130312_zps8dcedfaf.png

Figure 5 – US Drought Monitor map of drought conditions in the Southeast as of the 12th of March.

The shifts in the numbers in the table tell a good story.  Frequent storms tracked over this region recently, which helped bust the worst conditions (Severe and worse).  Look at the ‘None’ category now versus three months ago: the percent area doubled!  Now the rains need to continue through the rest of the year.

US drought conditions are related to Pacific and Atlantic sea surface temperature conditions.  Different natural oscillation phases preferentially condition environments for drought.  Droughts in the West tend to occur during the cool phases of the Interdecadal Pacific Oscillation and the El Nino-Southern Oscillation, for instance.  Beyond that, drought controls remain a significant unknown.  Population growth in the West in the 21st century means scientists and policymakers need to better understand what conditions are likeliest to generate multidecadal droughts, as have occurred in the past.

As drought affects regions differentially, their policy responses vary.  A growing number of water utilities recognize the need to be proactive with respect to drought impacts.  The last thing they want is their reliability to suffer.  Americans are privileged in that clean, fresh water flows when they turn their tap.  Crops continue to show up at their local stores despite terrible conditions in many areas of their own nation.  Power utilities continue to provide hydroelectric-generated energy.

That last point will change in a warming and drying future.  Regulations that limit the temperature of water discharged by power plants exist.  Warmer conditions include warmer water today than what existed 30 years ago.  Warmer water into a plant either mean warmer water out or a longer time spent in the plant, which reduces the amount of energy the plant can produce.  We can continue to generate the same amount of power if we are willing to sacrifice ecosystems which depend on a very narrow range of water temperatures.  As with other facets of climate change, technological innovation can help increase plant efficiency.


4 thoughts on “51.4% of the Contiguous United States in Moderate or Worse Drought – 12 Mar 2013

  1. I had an amazing 35-minute conversation with Guy McPherson on Wednesday. I say “amazing” because he says life where he is (southern New Mexico) will be impossible with 5 years – mainly because many proteins in plants begin to breakdown when temperatures exceed 50 Celsius. I am afraid that, if the Antarctica is the World’s freezer and the Arctic is the World’s air conditioner, the freezer would appear to have quite a few year’s use left in it but the A/C is knackered. Sadly, with most of the land being in the northern hemisphere, this is not good news. So, all I am afraid I can do is wish you good luck with defeating the Dunning-Krugger effect that enables so many people from places like Oklahoma to keep voting for ideologically-blinded people like James Inhoffe.

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  4. Pingback: 4th Daily April Record Low in Denver & Record Snow in Boulder | Weatherdem's Weblog

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