What is a 100 year or 500 year storm event?
The flood zones shown on the FIRM maps are based on the 100 and 500 year storms. These storms are rated according to how much rain falls within a certain time period. For example, on average once in one hundred years, a one percent chance, ten inches of rain will fall within a twenty-four hour time period in Savannah, so this type of storm would be considered a 100 year storm. A much higher rate of rainfall within a twenty-four time period would classify the storm as a 500 year storm. For example, a Category IV hurricane would be expected to drop twenty inches of rain in less than twenty-four hours. That would definitely qualify as a 500 year storm.

Show All Answers

1. What else can I do to prevent my house from flooding?
2. What is the difference between a Flood watch and Flood warning?
3. How do ponds prevent flooding?
4. What is the difference between a Retention Pond and a Detention Pond?
5. What is compensatory Storage?
6. Why can’t hydrostatic vents be used in the VE zone?
7. What are some of the main construction tips for the different zones?
8. How can I remove my property from the Floodplain?
9. What are benchmark, datum, and datum types?
10. I live in a low-risk flood zone. Do I really need flood insurance?
11. What is the Substantial Damage | Substantial Improved (SD/SI) aka “50% Rule” and Pre FIRM?
12. What is the Coastal Barrier Resources System (CBRS)?
13. What are the different Flood Zones and Risks?
14. What is a Freeboard?
15. What is the difference between Base Flood Elevation (BFE) and Design Base Flood Elevation (DBFE)?
16. What is a 100 year or 500 year storm event?
17. What is the Community Rating System (CRS)?
18. What is Increase Cost of Compliance (ICC)?
19. What is the National Flood Insurance Program (NFIP)?
20. What is the difference between the “Floodplain” and the “Special Flood Hazard Area (SFHA)”?
21. What is the City of Savannah’s Community Number?
22. Do marshes and other vegetation prevent flooding?
23. What is the Preferred Risk Policy (PRP)?
24. Is flood damage from wind-driven rain covered?
25. Can “north-eastern” winds affect flooding?
26. If I live in a flood zone but my finish floor is above the BFE, do I still need flood insurance?
27. Can I get flood insurance if I do not live in a High Risk Area?
28. Can I get flood insurance if I'm renting a property?
29. What types of property may be insured against flood loss?
30. Does my policy go into effect once a payment is made?
31. What is Flood Insurance?
32. What causes flooding in Savannah?
34. What is the Flood Insurance Rate Map (FIRM) used for?
35. Where can I get More Information?
36. How do I know if I am at risk of flooding?
37. What kinds of property are not insurable under the NFIP?
38. What are FIRM Panels and how many are there?
39. What is the purpose of an Elevation Certificate?