Hurricane Ian targeting Florida with 'life-threatening' storm surge, National Hurricane Center says. Here's what you need to know

Hurricane Ian is expected to bring life-threatening storm surge to several areas across Florida, but especially to the West Coast.

The National Hurricane Center warned the highest risk from storm surge will be from Fort Myers to the Tampa Bay region.

Residents in these areas should listen to advice given by local officials. Several evacuations have already been ordered along the coast in areas prone to flooding.

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The NHC forecast calls for Ian to reach Category 4 strength off the coast of Florida. While it could weaken before making landfall, it is still forecast to be a major hurricane —  with winds of at least 111 mph — when it comes ashore.

The Hurricane Center warned wind, storm surge and rainfall hazards will extend far from the center.

Ian storm surge in Florida: Here's what we know

Hurricane Ian forecasts at 5 a.m. Sept. 27, 2022.
Hurricane Ian forecasts at 5 a.m. Sept. 27, 2022.

Interactive map: Latest storm surge watches and warnings

Storm surge risk maps: Flooding vulnerability based on hurricane category 

Ian is likely to slow down as it approaches Florida, increasing the length of time a major storm surge and heavy rain will batter the coast, according to AccuWeather.

Storm surge may be the most significant threat, regardless of Ian's strength. AccuWeather forecasters said the storm poses a high risk to life and property across a significant portion of Florida.

"Based on a track with the eye of a major hurricane just offshore of Tampa, the Tampa Bay area can expect a water level rise of 6-10 feet," AccuWeather Hurricane Expert Dan Kottlowski said.

Dangerous storm surge won't be limited to Florida's west coast.

Areas along the St. Johns River, especially the Jacksonville area may be at risk for significant storm surge, according to AccuWeather. The combination of stiff easterly winds and heavy rain can push river and estuary levels to the point of significant flooding.

How high might the storm surge get?

The combination of storm surge and the tide will cause normally dry areas near the coast to be flooded by rising waters moving inland from the shoreline.

Water could reach the following heights above ground somewhere in the indicated areas if the peak surge occurs at the time of high tide:

  • Anclote River to Bonita Beach, including Tampa Bay and Charlotte Harbor: 5-10 feet

  • Suwannee River to Anclote River: 5-8 feet

  • Bonita Beach to Chokoloskee: 4-7 feet

  • Chokoloskee to East Cape Sable: 3-5 feet

  • Flagler/Volusia County Line to Altamaha Sound including St. Johns River: 2-4 feet

  • East Cape Sable to Card Sound Bridge including Florida Bay: 2-4 feet

  • Aucilla River to Suwannee River: 2-4 feet

  • Florida Keys including the Dry Tortugas: 2-4 feet

  • Indian Pass to Aucilla River: 1-3 feet

What is storm surge?

Along the coast, storm surge is often the greatest threat to life and property from a hurricane, according to the Hurricane Center.

Storm surge is an abnormal rise of water generated by a storm, over and above the predicted astronomical tides.

Storm surge is produced by water being pushed toward the shore by the force of the winds moving cyclonically around the storm. The impact on surge of the low pressure associated with intense storms is minimal in comparison to the water being forced toward the shore by the wind.

Storm surge is a complex phenomenon because it is sensitive to the slightest changes in storm intensity, forward speed, size, angle of approach to the coast, central pressure, and the shape and characteristics of coastal features such as bays and estuaries.

Adding to the destructive power of surge, battering waves may increase damage to buildings along the coast. Pounding by frequent waves can demolish any structure not specifically designed to withstand such forces. The two elements work together to increase the impact on land because the surge makes it possible for waves to extend inland.

In confined harbors, the combination of storm tides, waves and currents can severely damage marinas and boats. In estuaries and bayous, salt water intrusion endangers the public's health, kills vegetation, and can send animals, such as snakes and alligators, fleeing from flooded areas.

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This article originally appeared on Sarasota Herald-Tribune: Hurricane Ian could bring dangerous storm surge to some Florida areas