It is time to stop quivering in our boots in pointless fear of the future and just roll up our sleeves and build it.
- Ray Pierrehumbert

Wednesday, October 7, 2015

Seven Mississippi Rivers Over South Carolina

I calculated the water falling on South Carolina, ballparking it as an average depth of 0.25 meters falling over 2 days. 

It works out to 0.11 Sverdrups, which is a bit over half the discharge of the Amazon, but greater than any other river, about seven times the discharge of the Mississippi or St. Lawrence.

The atmospheric flux must have been much higher.

SC area 83e3 km2 = 8.3 e10 m^2
depth of flood = 0.25 m  
total water = 2e10 m3 
time = 2 days 
1e10 m3 /day at 86400 sec / day
= 115000 m3 / s = 0.115 Sv

20 comments:

Susan Anderson said...

Along with Joaquin headed for Portugal and Oho for BC. Interesting times ...

more OT: good little video from WHOI on algal blooms if anyone is interested:
http://www.whoi.edu/oceanus/feature/setting-a-watchman-for-harmful-algal-blooms

Tom said...

South Carolina got 18 inches of rain in 4 days. South Carolina's one-day precipitation record since 1890 is 14.80 inches.

When Typhoon Soudelor barreled through Taiwan recently, a nearby mountain village recorded 990 millimeters of rain. Basically 40 inches in one day. It was not a record. It was not even considered unusual.

I don't get it.

Tom said...

Maybe you can tease out the climate signal here: http://www.dnr.sc.gov/climate/sco/Publications/temp_study/precip_trends.php

Michael Tobis said...

I don't get what you don't get, Tom. I haven't started talking about climate relevance, though I intend to. The first installment will appear at And Then There's Physics momentarily.

It's a meteorologically interesting event in itself, and this post says nothing else.

SC's daily maximum rainfall at a single point is not relevant - we are talking about a very wide area. And of course, what happens to Taiwan in a typhoon is pretty much totally off topic. (The record daily rainfall in Texas beats Taiwan's, for what that's worth.)

Whether we count this SC event as part of a tropical storm or not is itself an interesting question!

Michael Tobis said...

Obviously seasonal precipitation tells us nothing about severe events, given that what we expect is fewer light rains and more frequent intense rains. So the total coming out in the wash in some region is no surprise. This is just looking for places where the signal isn't; you should leave that to the professionals like Roger Jr.

Michael Tobis said...

In fact, a daily local record for the state is likely.

"South Carolina's committee will surely be called upon to investigate the astronomical rainfall totals recorded this week, as some appear to surpass the standing record.

One possibility is the Weather Underground personal weather station on White Birch Circle in Columbia, which reported 18.71 inches of rain between 3:55 p.m. EDT on Oct. 3 and the same time Oct. 4.

The site piled up 17.72 inches on Oct. 4 itself, of which 15.12 inches – enough to break the 24-hour record – fell in less than 10 hours during the morning. However, a neighboring site about a mile away received only 7 inches of rain in 48 hours Oct. 3-4. Such a sharp difference may be evidence that one or both gauges is not properly calibrated.

In any case, several other sites may also have a case for claiming the new state record:

16.61 inches of rain between midnight and 10 p.m. Oct. 4 along Gills Creek in Columbia, according to the National Weather Service. The ensuing flash flood was so violent that it destroyed the official flood gauge there, but not before surpassing and nearly doubling the previous all-time record crest.
15.70 inches of rain betwen 12:44 p.m. Oct. 3 and 12:31 p.m. Oct. 4 at the South Carolina Department of Transportation office in Kingstree, according to its Weather Underground personal weather station.
15.02 inches of rain on Oct. 4 at the Weather Underground personal weather station in Dalzell, Sumter County."

http://www.weather.com/news/news/south-carolina-historic-flood-rainfall-record-extreme

Michael Tobis said...

See also https://andthentheresphysics.wordpress.com/2015/10/07/if-i-had-ever-been-here-before-i-would-probably-know-just-what-to-do/

Tom said...

I read your post over at ATTP. I've never been allowed to comment there, a pre-emptive strike by ATTP that you might sympathize with.

There's an apocryphal story about an English professor who spent his career trying to prove that the Iliad wasn't written by Homer, but by another Greek with the same name.

There are elements of your post that remind me of that story. The first is Trenberth's assertion that there is a new normal, that the climate has changed and that this change 'infects' every meteorological phenomenon.

As a Lukewarmer, I can be expected to challenge that assertion--and I do. We've had this conversation after every extreme weather event over the past 7 years, so why should rain in South Carolina be different?

I offer as example the assertion that the current California drought is 'outside the norm.' It is not. California has frequently had droughts of greater severity and duration than the current drought, some lasting for centuries. The same is true for Pakistani floods and Russian heatwaves. A combination of much higher populations and increased access to modern media is a better explanation of the 'new normal' than changes to the climate.

As skeptics (and we lukewarmers) frequently mention, there are no measurable changes in much of what you are writing about. There has been no change in global drought over the past 100 years. Heatwaves in France like the one that caused so much loss of life are called 'canicules' and have been documented for centuries. Storm intensity and frequency have if anything decreased in recent decades. Trends in flooding are very hard to capture, due to the structure of data capture efforts, but the fact that reports of intense flooding occur in areas with recent dramatic increases in population, which increases the number in harm's way, do not help us understand if it is increasing or not.

If the new normal is the same as the old normal, we are like the professor attributing the Iliad to another Greek with the same name. Or to use a more recent line, 'Meet the new boss--same as the old boss.'

Michael Tobis said...

Are you saying the climate hasn't changed? Or that the climate has changed, but coincidentally the distribution of severe events is exactly the same as before? Or that it's the same except for the parts where it has gotten more benign?

If you have a story please stick to it.



Tom said...

It's not a story yet. It's a series of observations.

Of course the climate has changed. It's 0.8C warmer. But because so much of the warming has occurred in the Arctic, the rest of the world hasn't seen dramatic temperature rises and hasn't suffered notably different impacts. For every instance of extreme weather that has been associated with human contributions to global warming, there are clear examples of equivalent events in the same region.

Rising temperatures in the Arctic have clearly impacted the regional climate. Some of that tails down into the upper reaches of the Northern Hemisphere.

But globally? Globally the drought index hasn't changed in the past 100 years. Storms really don't seem to be getting 'more intense', pace Sandy and South Carolina. Here in Asia they don't think so, anyhow.

I don't honestly think we can say too many intelligent things about floods right now, given the state of data collection. Improved technology is bringing the news about events to us that we would not have recorded in the past. It is also working to lessen impacts, especially loss of life, which in the past, especially regarding floods, was just about the only metric recorded.

I think there's a helluva story out there waiting to be told. I just don't think we know the plotline yet.

Tom said...

In case you would like to discuss this elsewhere, https://thelukewarmersway.wordpress.com/2015/10/08/south-carolinas-disaster-tango/

andthentheresphysics said...
This comment has been removed by a blog administrator.
Tom said...
This comment has been removed by a blog administrator.
Tom said...
This comment has been removed by a blog administrator.
andthentheresphysics said...
This comment has been removed by a blog administrator.
Michael Tobis said...

Well, good morning...

As is so often the case the thread is somehow about Tom. Yawn. Deleting a bunch of stuff, some by Tom's own request.

Tom said...

wasn't any of my doing

Tom said...

If you were playing fairly you wouldn't say this blog is somehow about Tom, which carries the clear inference that it is my doing. You would note that ATTP came here and posted about me and not about the topic, that I responded and later asked you to remove my response as I was tired of this shit.

Which I thoroughly am.

Tom said...

https://thelukewarmersway.wordpress.com/2015/10/10/after-the-gold-rush/

Tom said...

You might find this interesting if you are building a database with regards to recurrence of climatic phenomena: http://www.nature.com/nature/journal/v491/n7424/abs/nature11575.html