[StBernard] 100 year storm or flood

[Westley Annis]

Hey Deborah,
 
the bottom line is right-  other countries use much more stringent models than we do.  just follow the money and one usually finds the answers to most questions.
 
God Bless,
Craig


-----Original Message-----
I asked the president of the LA American Society of Civil Engrs about
the article he wrote which I posted  excerpts from awhile back, vs. the
response of his co-worker at the Corps to Craig about the 100 year
event.

While both Corps employees are right, think of it this way. Craig's
source is basing it on the probability of it happening in any given
year. Much like flipping a coin, the probability is 50%, or 1 out of 2
times, or 500,000 out of 1,000,000 times. The coin doesn't know what
happened before or after.

My source used an additional equation that factors in how often one
could expect an event.  Wouldn't you expect that if a coin was tossed
100 times, that there is a greater expectation that if it came up heads
75 times in a row, that statistically you could expect to see tails?
This doesn't mean it will be tails because 100 coin tosses is a very
small statistical sample compared to a million tosses. 

I have been at a casino where red came up 19 times on the roulette
wheel before zero, double zero, or black. Now that happens from time to
time, but it is so rare that the same color comes up more than 6 times
consecutively that people were running across the floor to bet a hundred
dollars or more that the next sping would NOT be red again.

So you can read Tim's message and quote from the National Flood
Insurance program that says during a 30 year time span, the chance is
expected to be 26% that the 100 years storm hits.  This is taking into
account the formula for an event of a certain probability occuring over
a longer number of "tries", be it roulette spins, coin tosses, or
years.

The bottom line is the same-100 years is not nearly as safe as what
other countries consider acceptable to protect its people.  
************************************
Deborah,
 
For further illumination of our discussion yesterday, I am sending the
attached publication from FEMA that explains the rationale and workings
of the National Flood Insurance Program.  It includes my not-so-original
revelation that the 100-yr level of protection is not all that great. 
It notes:
 
"The 1-percent-annual-chance flood was chosen on the basis that it
provides a higher level of protection while not imposing overly
stringent requirements or the burden of excessive costs on property
owners. The 1-percent-annual-chance flood (or 100-year flood) represents
a magnitude and frequency that has a statistical probability of being
equaled or exceeded in any given year, or, stated alternatively, the
100-year flood has a 26 percent (or 1 in 4) chance of occurring over the
life of a 30-year mortgage."
 
Regards,
 
Tim