Catastrophic Flooding in South Carolina

frances50 · #1 10-05-2015, 09:38 AM

I live near the Columbia, South Carolina area and I just wanted to reach out to all AGF members from the state. Hope everyone is safe and here's praying for this flooding to subside. Then there will be the clean up and checking the roads and bridges. I think this must be the worst state wide disaster in history for us. Damage appears to be wide spread. I was lucky and only have some major road damage out my way in Sandy Run. I live on a 54 acre lake and fortunately, the HOA took the riser boards out so our lake didn't overflow. Our dirt road is damaged and I'm not sure I can get out of my subdivision. But overall, I was lucky.

BoneDigger · #2 10-05-2015, 02:24 PM

All of my family lives in the lowcountry. All are well but there is a lot of damage.

Sent from a cell phone. Sorry for any typos.

Jim Owen · #3 10-05-2015, 02:31 PM

I'm thinking of all ya'll. It's got to be the worst flooding in that part of the state in my lifetime.

Keep safe.

Chicago Sandy · #4 10-05-2015, 10:00 PM

Heartbreaking to watch--especially with all Charleston’s been through this year.

clintj · #5 10-06-2015, 04:15 AM

I was born and raised in Aiken, and the pictures on the news are just unbelievable. That pic of the Broad River just a few feet from the I-20 bridge deck, for example. I'm used to seeing it quite a good distance below when driving over.

Stay safe there, folks! Hopefully the waters recede quickly for you.

Sent from my SM-G920V using Tapatalk

D. Shelton · #6 10-06-2015, 03:18 PM

I can't imagine what that's like ! Parts of SC got 4 years worth of NM rain... it's really impossible to think of that much water here in a few days. The Rio Grande would wash away much of civilization here. I suppose it's lucky so few died in the SC floods

Andromeda · #7 10-06-2015, 07:37 PM

My daughter lives in Summerville SC and is safe and sound and escaped the worst of the flooding.

HDRider · #8 10-06-2015, 08:05 PM

My girlfriend's daughter and son in law live in Summerville. They're in good shape.

As a complete aside, a question I have is this: They're calling it "1,000 year flooding".

How would they know?

frances50 · #9 10-07-2015, 10:54 AM

Quote:

Originally Posted by HDRider

My girlfriend's daughter and son in law live in Summerville. They're in good shape.

As a complete aside, a question I have is this: They're calling it "1,000 year flooding".

How would they know?

That quote came from our grand governor herself.

radiokid · #10 10-07-2015, 11:50 AM

Quote:

Originally Posted by HDRider

My girlfriend's daughter and son in law live in Summerville. They're in good shape.

As a complete aside, a question I have is this: They're calling it "1,000 year flooding".

How would they know?

Geologic record.

posternutbag · #11 10-07-2015, 12:08 PM

Quote:

Originally Posted by HDRider

My girlfriend's daughter and son in law live in Summerville. They're in good shape.

As a complete aside, a question I have is this: They're calling it "1,000 year flooding".

How would they know?

On some level, it is an estimation, a best guess, if you will. The evidence used to make this "guess" include historic accounts (very useful for determining 100 year flood events, which are what are typically used in actuarial models to determine flood insurance rates), sedimentation deposits and other geologic data as well as physical process models. In a tidal estuarine environment like coastal South Carolina this can be tricky.

Charleston and other coastal areas did not flood as badly as the midlands of SC because the estuaries can accept a great deal of run-off, and when and were Charleston did flood, it was primarily tidal, which is why there are a couple of people in this thread with loved ones in Summerville who were less adversely effected (Summerville is about 15 miles inland). The people along the coast who were impacted tended to be those living in natural drainage basins, or whose property was very near sea level, in other words, tidal areas.

The midlands around Columbia was a very different story. Several dams overflowed because there just wasn't anywhere to put the storm run-off. That is where you saw the catastrophic damage and the pictures of roads being washed out.

architype · #12 10-07-2015, 12:14 PM

Well, if it ever floods like this in Kentucky, we have, (will have), our very own "Ark Park". I know where I'm heading.

mc1 · #13 10-07-2015, 12:17 PM

Quote:

Originally Posted by HDRider

My girlfriend's daughter and son in law live in Summerville. They're in good shape.

As a complete aside, a question I have is this: They're calling it "1,000 year flooding".

How would they know?

The 1,000-year event flooding that hit South Carolina means everyone there can forget about flood insurance until the year 3015, right? Not even close, according to scientists who say terms like "1,000-year event" are widely misunderstood and less accurate because of Earth's changing climate.

A "rain event like South Carolina doesn't necessarily ... happen every 1,000 years," tweeted meteorologist Marshall Shepherd of the University of Georgia, who's also a host for the Weather Channel and past president of the American Meteorological Society.

"(It) is apparent to me that many people still do not understand the concept of what 100- or 1,000-year rain event means," he also noted in his blog. "Many people literally assume it means this event 'can only' happen every 1,000 years."

But one extreme event does nothing to prevent another, any more than one flip of a coin influences the next. They are separate, independent events that answer only to the laws of probability.

...

To understand what "1,000-year event" means, it's better to think like a bookie. It's all about the odds. In this case the odds of a three-day rainfall amount of 17.1 inches for Charleston and 14.2 inches for Columbia are 1 in 1,000 years, explained Henson and Masters. Likewise, the 1-in-1,000-year rainfall amount over 24 hours for Charleston is calculated to be 14.8 inches and for Columbia, 12.5 inches.

The U.S. Geological Survey (USGS) uses these sorts of statistics to understand stream and river flows, which are naturally tied to precipitation. On their water resources website the agency explains that the interval of an event recurring is based on the probability that the event will be equaled or exceeded in any given year. This year there was a 1-in-1,000 chance of the rainfall and flooding seen in South Carolina. Next year there will be the same odds.

more here:
http://news.discovery.com/earth/weat...orm-151006.htm

Rodger Knox · #14 10-07-2015, 01:31 PM

The return frequency is the reciprocal of the probability of the event occurring in a given period.
For rainfall events, a 100 year storm has a 1% chance of occurring in a year.
A 1000 year storm has a 0.1% chance.
The probability is calculated from rainfall statistics, and for the statistics to have any real meaning, the period of record needs to be comparable to the return frequency being determined. That is, you need about 100 years of records to determine a 100 year storm.
A 1000 year storm is at best an extrapolation, at least in the US.