Thursday, August 9, 2012

South Carolina Drought Update

Three months ago 99% of South Carolina was in a moderate drought or worse.  About 35% was in an extreme drought and it seemed to be getting worse.  Then the rains began to appear in mid-May.  This continued through mid-June and then the rains stopped.  It became brutally hot with some areas breaking all-time record highs.  The corn crop in the western part of the state suffered from the flash drought conditions.

The heat continued through much of July and it was the third hottest July on record for South Carolina.  We joined much of the central and eastern part of the country in that respect.

Average July Temperature rankings.  Image Credit: NOAA/NCDC.
Rains continued to fall across July with Columbia receiving over 9 inches of rain in the city.  The heavy downpours resulted in several instances of flooding of Rocky Branch Creek.

Flooding of the Rocky Branch Creek on June 11, 2012.  Image Credit: USGS.

It also occurred in June from some heavy rains in the middle of month.  This was a bit ironic occurring in the midst of a drought.  However, there have been five extreme rainfall events at the airport and city in the past three months.

The latest US Drought Monitor was released today.  It showed improvement in all areas of South Carolina.  Only 62% of the state is now in a moderate drought or worse.  The west central part of the state near the Savannah River continues to be the worst hit area.

The Drought Monitor for South Carolina.  Click on the graphic for a larger view.  Image Credit: USDA.

Rains have continues to fall albeit sporadically over the past three months.  Much of the Midlands have seen between 15 to 25 inches of rain since May 9.  The maps below show the observed rainfall for the period of May 9 through August 8.

Top image:  The observed rainfall for the period of May 9 - August 8.  Bottom image: The rainfall anomalies measured in inches from normal.  Click on either image for a larger view.  Image Credit: NOAA/AHPS.

Typically at this time of year the rain comes from thunderstorms.  This tends to be spotty producing pockets of heavier rain.  This can be seen in the rainfall map.  It accounts for the wide range of rainfall over the past three months.  Rainfall in the southern third of South Carolina was also helped by Tropical Depression Beryl.

In spite of the recent rains, it will take much more to end the drought.  An additional 9 to 15 inches of rain is needed over the next two months to end the drought in the western part of the state.  This is unlikely, but additional rain will certainly ease the drought conditions.