More extensive curtainwall failures with some complete failure of roof systems on many small residences. Major erosion of beach areas. Terrain may be flooded well inland. Complete roof failure on many residences and industrial buildings. Some complete building failures with small utility buildings blown over or away.
Flooding causes major damage to lower floors of all structures near the shoreline.
Massive evacuations of residential areas may be required. An abnormal rise in sea level accompanying a hurricane or other intense storm and whose height is the difference between the observed level of the sea surface and the level that would have occurred in the absence of the cyclone. Storm surge is usually estimated by subtracting the normal or astronomic tide from the observed storm tide. The actual level of sea water resulting from the astronomic tide combined with the storm surge. If the storm comes ashore during astronomical low tide, the surge will be decreased by the amount of the low tide.