re: Hearing stories of self home reconstruction

quote:

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I doubt you see anything like that. This flood event was a 1:1000 year event. You just simply don't build to withstand a 1:1000 year flood.

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- This was well beyond a 1,000 year flood, which makes it all even more ridiculous.


"Southern Regional Climate Center (SRCC)
August 31 at 7:40am ·

Louisiana Storm was Greater Than 1000-Year Event

Barry Keim, Louisiana State Climatologist, Louisiana State University

South Louisiana is still reeling from the torrential rainfall that hit our State on August 11-13. In fact, recovery from this event will be on the order of months to years, rather than days to weeks. The reason being is that storm is one for the record books (Figure 1). Up to this point, I’ve only had time to examine the two-day rainfall totals (I still need to examine 3-day and 4-day totals), but this storm is beyond impressive. With help of my associate Alan Black at LSU, we determined that the largest 2-day rainfall total ever recorded in Louisiana was 24.46 inches recorded at the Abita Springs on May 9-10, 1995. We have 3 locations that exceeded that total in this event. Let’s pause for a minute.

To put these 2-day rainfall totals in some perspective, a 100-year event at Baton Rouge is 14.2 inches, as depicted by NOAA Atlas 14. This same document notes that a 1000-year event is 21.3 inches. So what does this mean? A 100-year event has a 1 percent chance of being equaled or exceeded in any given year, and if we had many hundreds of years of data, you would expect approximately 1 event per century of data. Note that these would NOT be evenly spaced-out over time however, as you could 2 or 3 “hundred year events” in one century, and none the following century. A 1000-year event has a one-tenth of 1 percent chance of occurring in any given year. Bottom line…..these events are extremely rare. With all that said, south Louisiana had 9 locations that exceeded a 1000-year event for their given location. Most of these were in East Baton Rouge and Livingston Parishes. The three wettest sites over a 2-day period were Denham Springs with 25.5 inches, Brownfields in North Baton Rouge at 26.83, and Watson with an incredible 31.39 inches! All three were record-breaking! When you step back and think about this for a moment, this Watson measurement is over twice the volume of rainfall expected in a 100-year event, and it is still a 10-inches greater than the 1000-year estimate! The Watson rainfall total is also nearly 7 inches larger than the previous record over this 2-day duration. These are clearly crazy times in South Louisiana, and it will take time, and plenty of it, to recover from the wounds inflicted. E-mail me with questions or feedback at keim@lsu.edu."