I'm sure I just saw the governor of South Carolina say that the state
had received its heaviest rainfall for a thousand years (about 40 cm I
believe).

While that is rather a lot of rain, I wonder how they can possibly know
how much rain fell from October 1015 to date.


--
AS
http://nature.opcop.org.uk
I knew the Triffids were real when I saw the signs
Caution: Heavy plant crossing

On Monday, October 5, 2015 at 1:23:05 PM UTC+1, Asha Santon wrote:
I'm sure I just saw the governor of South Carolina say that the state
had received its heaviest rainfall for a thousand years (about 40 cm I
believe).

While that is rather a lot of rain, I wonder how they can possibly know
how much rain fell from October 1015 to date.

Wasn't it more along the lines of a once in 1000 year event, a 'return period' in other words?
However to calculate such a return period from actual rainfall data that cannot span much more than one tenth that timespan must be pushing the statistics to the extreme.....

Col

wrote:

On Monday, October 5, 2015 at 1:23:05 PM UTC+1, Asha Santon wrote:
I'm sure I just saw the governor of South Carolina say that the state
had received its heaviest rainfall for a thousand years (about 40 cm I
believe).

While that is rather a lot of rain, I wonder how they can possibly know
how much rain fell from October 1015 to date.

Wasn't it more along the lines of a once in 1000 year event, a 'return
period' in other words? However to calculate such a return period from
actual rainfall data that cannot span much more than one tenth that timespan
must be pushing the statistics to the extreme.....

Col

Indeed. The usual rule of thumb is that it is unrealistic to calculate data for
return periods that are longer than 3 times the length of the available dataset.

--
Norman Lynagh
Tideswell, Derbyshire
303m a.s.l.
http://peakdistrictweather.org