I wonder what type of flood the floods Ondoy brought were? I’m guessing probably a toss up between 50 and 100 year floods.
100-year floods
By Andrew Gelman on March 25, 2011 9:37 AM | 5 Comments
According to the National Weather Service:
What is a 100 year flood? A 100 year flood is an event that statistically has a 1% chance of occurring in any given year. A 500 year flood has a .2% chance of occurring and a 1000 year flood has a .1% chance of occurring.
The accompanying map shows a part of Tennessee that in May 2010 had 1000-year levels of flooding.
At first, it seems hard to believe that a 1000-year flood would have just happened to occur last year. But then, this is just a 1000-year flood for that particular place. I don’t really have a sense of the statistics of these events. How many 100-year, 500-year, and 1000-year flood events have been recorded by the Weather Service, and when have they occurred?
via 100-year floods – Statistical Modeling, Causal Inference, and Social Science.