As promised, the National Hurricane Center will start using an experimental potential storm surge flooding map this season.
Storm surge, not rain-driven flooding or high winds, often is the biggest killer in a hurricane.
Hurricane Center director Rick Knabb said at last year’s Florida Hurricane Conference in Fort Lauderdale that his operation would begin displaying experimental graphics showing potential storm surge. Watches would be delineated independent of whatever evacuation borders counties have set.
Knabb said at the time that the center would start putting storm surge watches and warnings in place as early as 2015.
Both this year’s storm surge maps and the watches and warnings added in 2015 likely would be experimental for two years.
The hurricane center said Friday that the maps issued this year will show where storm surge could occur and how high above ground the water could reach in those areas.
The first map usually will be issued as the same time as the first hurricane or tropical storm watch. Maps show flooding levels that have a 10 percent chance of being exceeded — a worse-case scenario. Maps are subject to change every six hours as each new forecast advisory is issued, but won’t be available until 45 minutes to an hour after the advisory.
Storm surge potential is far more severe in the Miami area, where Hurricane Andrew deposited sailboats in trees and freighters on top of flood gates, and especially in southwest Florida, where the sloping landscape provides the potential for standing water dozens of miles inland.
It’s not as dramatic a factor in Palm Beach County and the Treasure Coast, because the ocean floor drops off precipitously just off the coast and the deep water absorbs much of the energy of a storm surge. The region also benefits from several ridges.
But the damage is less, not zero.
A June study said three Palm Beach County ZIP codes — 33480 (Palm Beach), 33410 (Palm Beach Gardens) and 33458 (Jupiter) — remain in the top 10 in South Florida in terms of potential storm surge loss because of the combination of surge risk and high property values.
Scientists have said that, even in a minimal storm, water would cover most or all barrier islands and the mainland right along the Intracoastal Waterway, and in a Category 5 storm the ocean could rise up to 10 feet above normal in coastal Palm Beach County and up to 15 feet on the Treasure Coast.