NEW ORLEANS, La. (WVUE) - The high water from Cristobal while forecasted still came as a shock for some. After witnessing the water come up along the Mandeville lakefront resident David Cambre was surprised. He said, “Knowing how high the lake was, I knew it would happen. I just didn't expect to wake up to this.”
Some locals expressed confusion at the Hurricane Center’s forecast using feet above ground. Jaime Rhome the storm surge specialist at the National Hurricane center said, “The simplest way to explain above ground is if you walked to the beach or walked to the coastline and stuck your toes in the water’s edge at high tide five feet above ground would be at your neck and six feet would be above your head on a normal height person."
Rhome said when the Hurricane Center attempted to find the best way to talk about surge height surveys showed less than 15 percent of people knew how high above sea level their property sits.
For those that do the "above ground" number may seem off.
For example during Cristobal in Waveland, MS gauge’s that measure from mean sea level showed seven feet of water. Rhome explains, “At the surface it looks like our forecast was too low, but when you actually do the conversion and line apples to apples up you see that the forecast comes out to be quite accurate in the case of Cristobal.”
He said if you are in an area expecting to see any storm surge there is a more detailed map. "Remember we are working with a large spectrum of users ranging from the individual citizen in coastal Louisiana all the way up to the highest level of the government where we're trying to convey which state or which portion of a state is going to be impacted," said Rhome.
The storm surge inundation map gives a neighborhood level forecast that considers the height of the land. How far it is from the coast and canals, wetlands, and other low-lying pathways water can use to find its way inland.
Rhome said, “We have these high-resolution inundation maps which show detailed information about where the water will go and not go and it takes into account very high-resolution information about the height of the land." These more detailed maps can help you decide if your home is at risk.
Another thing to keep in mind is that both the broad range and the more precise forecast are worst case scenarios.
The storm surge inundation map is active once watches and warnings begin.
You can access it on the National Hurricane Center web page.