JACKSONVILLE, Fla. -- Florida faces a lot of severe weather and one of the major impacts during tropical weather is storm surge. Storm surge is one of the most dangerous hazards of a tropical storm or hurricane. It is an abnormal rise of water generated by a storm that goes even over and above the predicted astronomical tides.

About half of the deaths associated with landfalling tropical cyclones over the past fifty years has been linked to storm surge flooding, according to a 2014 National Hurricane Center study. To help highlight this danger, the NHC has created a watch and warning product.

The prototype of the Storm Surge Watches and Warnings were used during Hurricane Matthew. However, the first operational Storm Surge Watch was issued Wednesday, August 23, 2017 ahead of Tropical Depression Harvey approaching the southeast coast of Texas.

storm surge watch

A Storm Surge Warning is defined as the danger of life-threatening inundation from rising water moving inland from the shoreline somewhere within the specified area, generally within 36 hours, in association with a tropical, sub-tropical, or post-tropical cyclone. A Storm Surge Watch is generally issued within 48 hours.

Along with these watches and warnings comes a Potential Storm Surge Flooding Map, which is based on the forecast track, intensity, and size of a tropical storm or hurricane. However, it’s important to note this map does not represent a forecast of expected inundation. Instead, this map is intended to provide a reasonable worst-case scenario – the amount of inundation that has a 10-percent chance of being exceeded at each individual location.

Storm surge is a very complex phenomenon because it is sensitive to the slightest changes in storm intensity, forward speed, size, angle of its approach to the coast, central pressure, and the shape and characteristics of coastal features. With the newly released storm surge watch and warning product, the NHC hopes these advisories will serve as a call to action for people in the path of a storm to listen to evacuation orders.