Little did we know that the winter storm at the end of January would be the prelude to a bigger storm two weeks later (February 11-13). A complex storm system came through South Carolina in two waves. The first occurred on Tuesday with snow over the northern Midlands and rain/sleet elsewhere. This was followed by the main batch of precipitation on Wednesday ending Thursday morning.
Most of the snow occurred over the northern half of the Midlands. It was mainly sleet with some snow in Columbia, but the precipitation became more snow farther north. The northern most counties of the Midlands saw a considerable snowfall.
|Total snowfall as of 7 a.m. Thursday, February 13, 2014. This is based on observations from the National Weather Service Forecast Office in Columbia, SC. Image Credit: WLTX-TV.|
South of Columbia it will a sleet/freezing rain mix. The farther south you went the more freezing rain occurred. The southern Midlands saw the greatest accumulation of ice as shown on the map below.
|Total ice accumulation as of 7 a.m. Thursday, February 13, 2014. This is based on observations from the National Weather Service Forecast Office in Columbia, SC. Image Credit: WLTX-TV.|
The Midlands ended up on the dividing line between snow and ice. The northern half saw a snowstorm while for the southern half saw an ice storm. Travel became difficult if not impossible through some sections. The worst of the storm occurred over the southern Midlands with the accumulation of ice. An estimated 350,000 people lost power at the end of the storm. Some were without power for over a week. Schools remained closed for Wednesday through Friday with some of the northern counties closing schools on Tuesday.
As if this were not enough an earthquake struck Friday evening, February 14, near Edgefield, SC. The earthquake was a magnitude 4.1 and struck at 10:23:38 lasting about 10 seconds. It was felt all over the Carolinas and Georgia, however no significant damage was reported. A magnitude 3.2 aftershock occurred two days later.
How did the forecast perform?
I mentioned in the previous posts that this was an exceedingly difficult forecast for both timing and amounts. However, the forecast did surprisingly well. There was a band of snow that moved across the northern half of the Midlands on Tuesday followed by a wintry mix on Wednesday.
|Forecast for snow as of 7 a.m. Wednesday, February 12, 2014. This was for the first surge of moisture moving through the Midlands on Tuesday. Image Credit: WLTX-TV.|
A wedge of cold air covered much of South Carolina on Wednesday as temperatures barely made it to freezing. The overrunning of moisture created a band of snow across the northern Midlands and sleet/freezing rain over the southern Midlands. Columbia received a little of everything. The forecast for ice was quite good in both areal extent and amount. There were forecasts in the media of ice up to 2 inches, but I could not find examples of this in the historical record so I did not think this likely. The most recent example of ice accumulation was with the winter storm in 2004 and the ice buildup was a quarter to a half inch.
|Forecast for ice accumulation as of 7 p.m. Wednesday, February 12, 2014. This was for the second surge of moisture moving through the Midlands on Wednesday & Thursday morning. Image Credit: WLTX-TV.|
There was little additional ice accumulation Wednesday night into Thursday morning, but there was another burst of snow before it all ended Thursday morning. This led to another snow forecast made on Tuesday to add in the additional snow that would fall on Wednesday and Thursday morning.
|Forecast for snow accumulation as of 7 a.m. Thursday, February 13, 2014. This was for the second surge of moisture moving through the Midlands on Wednesday & Thursday morning. Image Credit: WLTX-TV.|
These forecasts were aided by the superior performance of the GFS model run by the National Oceanic & Atmospheric Administration (NOAA). Details were filled in by our RPM model run by WSI. This is the second winter storm to hit South Carolina this winter and the GFS has been the superior model.
How does this winter storm compare with the recent past?
The most recent example of a winter storm that compares with this storm was the one that moved through the region January 24-26, 2004. The scenario for this storm was a little different and can be read here. This storm resulted in power outages to about 175,000 customers and some were without power for almost a week.
|Accumulation of snow and ice from the winter storm in 2004. The purple areas are for ice while the gray and blue areas refer to snow. Image Credit: South Carolina Climatology Office.|
|Accumulation of ice from the winter storm in 2004. Image Credit: NOAA/NWS.|
The winter storm this year was worse than the one in 2004. Both the snow and ice accumulations were higher with up to 10 inches of snow in the northern Midlands and ice up the 1 ¼ inches thick in the southern Midlands. All areas in between had varying amounts of both. The number of customers without power was about twice that of the 2004 storm. A few rural areas were still without power more than a week after the storm.
One common element in both storms was the difficulty in forecasting the various forms of the precipitation. Model computer technology and some skillful forecasting produced a better forecast this time.