The U.S. metropolitan area most vulnerable to storm surge damage is Tampa/St. Louis. St. Petersburg. That's according to a 2015 report by Karen Clark & Company, “America's Cities Most Vulnerable to Storm Surge Flooding.” Their once-in-a-century storm (1% chance of occurring in any year) is a Category 4 hurricane with winds of 150 mph (240 km/h). Such a storm hitting north of Tampa Bay is expected to cause $230 billion ($2,024) in damage – from storm surge alone.
Tampa Bay is not frequently hit by hurricanes because the city faces the ocean to the west, and the east-west trade winds prevailing at that latitude make it unusual for storms to hit the west coast directly from the ocean in Florida. This is fortunate because the vast expanse of shallow continental shelf waters offshore Tampa Bay (less than 300 feet deep and 90 miles offshore) are conducive to the development of massive storm surges.
The last time Tampa was hit directly by a hurricane was in 1946, when a Category 1 storm moved across the bay. The Tampa Bay Hurricane on October 25, 1921 was the last major hurricane to make landfall in the Tampa Bay area. This low-end Category 3 storm made landfall with winds of 115 mph (185 km/h), brought a storm surge of 10-11.5 ft (3-3.5 m), and caused severe damage ($180 million, 2024 USD ). A storm surge of 15 feet (4.6 m) was detected in what is now downtown Tampa, and the Pinellas County peninsula where St. Petersburg is located was inundated, turning St. Petersburg into an island. Most of the few human structures in the area at the time were destroyed.
When the hurricane struck Tampa Bay in 1921, approximately 160,000 residents lived in the four-county area, most of them in higher-lying communities. Today, the area has more than 3.5 million residents, and this number is growing at the rate of approximately 50,000 people every year. Sea levels are about a foot higher now than they were in 1921, so a storm surge from the same storm can cause more damage. A 2007 study by Tufts University in Florida and the Department of Climate Change found that 2.25 feet (0.7 m) of sea level rise – which many scientists predict will occur by the end of the century – would put 152,000 people living in the Pekinese Russ County (where St. Petersburg is located) is underwater at high tide.
The majority of the population in the four Tampa Bay area counties lives in low-lying coastal areas, with about 50 percent of the population living below 10 feet above sea level. According to the 2010 Tampa Bay Area Statewide Regional Evacuation Study, more than 800,000 people live in evacuation zones for Category 1 hurricanes and 2 million people live in evacuation zones for Category 5 hurricanes. Given that only 46 percent of the area's Category 1 hurricane evacuation zones were evacuated when evacuation orders were issued in 2004 when Category 4 Hurricane Charley threatened the region, the next major hurricane is likely to cause significant casualties.
According to the second of an excellent two-part series published in 2022 by the Tampa Bay Times, 11% of properties in Tampa are at risk of flooding from a Category 1 hurricane. In Pinellas County (home to St. Petersburg and home to nearly 1 million people), the number is 20 percent, with nearly $30 billion in property. No county in Florida has so many structures and such a high risk value, the article reports: “More than 700 critical properties such as places of worship, gas stations, schools, government buildings and public facilities are at risk from Level 1 flooding. Level 2 The storm exposed more than 500 hotels, mostly near Pinellas' famous beaches, to the storm.
Hurricane Helen
Tampa's extreme vulnerability to hurricane storm surges was laid bare last month. Although its center passed 130 miles (205 kilometers) west of Tampa Bay on September 26, Hurricane Helene brought the worst storm surge ever recorded to the bay since 1947, with water levels 5 to 8 feet above dry ground. . According to local television station fox13news.com, four counties in the Tampa Bay area were severely damaged: 28,000 structures were damaged in Pinellas County (home to St. Petersburg), 9,900 in Pasco County, Manatee County and Sarawak County. A total of 8,600 buildings were damaged in Sota County. There were 12 storm-related deaths in Pinellas County, two in Manatee County and two in Hillsborough County.
Damage in Manatee and Sarasota counties alone is estimated at $1.1 billion. Damage estimates for other counties are not yet known, but since Pinellas and Pasco counties have more than four times the number of damaged structures than Manatee and Sarasota counties, we expect billions of dollars in damage The additional damage made Helen the most destructive hurricane on record for Tampa Bay.
Additional estimates of hurricane risk for Tampa Bay
In 2010, the Tampa Bay Regional Planning Commission launched the Tampa Bay Disaster Plan, which envisioned Category 5 “Hurricane Phoenix” hitting downtown Tampa with 160 mph winds and a 26-foot storm surge. The study projected about 2,000 deaths and nearly $250 billion in losses in the city.
In 2016, Dr. Peter Sousounis, a meteorologist at risk modeling firm AIR Worldwide, told me in an email that their most damaging event in Tampa Bay was one with sustained winds of 220 mph (355 kph) Category 5 storm, hitting Manatee County with a central pressure of 887 mb. This nightmare storm caused $290 billion in insured losses (2024 USD) in four counties (Manatee, Pinellas, Pasco and Hillsborough counties) – for those 1 in 10,000 For counties with long recurrence intervals, this is a level of loss. Because uninsured losses from hurricane strikes are typically about the same as insured losses, total losses from the storm could be as high as $400 billion.
Tampa's 'Category 6' hurricane: Incredible 830 MB storm with 233 mph winds
But Kerry Emanuel of MIT and Ning Lin of Princeton University outlined the ultimate worst-case scenario for Tampa in their 2015 paper “Grey Swan Tropical Cyclones” (press release available here). The chance that a Category 5 hurricane could bring a storm surge of 26-36 feet (8-11 m) to Tampa in late 20th century weather is extremely low or negligible, but the estimated chance of occurrence is 1 in 5,000 to 15 One in 10,000 events that occurred at the end of the 21st century. We may need to invent a “Category 6” name for the 150,000-year storm that appeared in their simulations – a run of the HADGEM climate model showed an unimaginably strong hurricane with a central pressure of 830 mb and top sustained winds of 233 mph (375 km/h), following the correct path parallel to the coast, producing a massive 36 ft (11 m) storm surge in Tampa Bay. Even allowing for a 15% reduction in winds due to land friction, the winds produced by such a Category 6 hurricane would be similar to those of the EF5 tornado that flattened Joplin, Missouri, except that the EF4 to EF5 damage would be along a line Belt spread.
Paper published by Columbia University hurricane scientist Adam Sobel and colleagues in July 2016 scienceHuman Impact on Tropical Cyclone Intensity, states that we expect winds in the strongest hurricanes to increase by about 2.2 mph (1 m/s) per decade, or about 19 mph by 2100. Hurricane Patricia (Mexico's Pacific Coast) has sustained winds of 233 mph (375 km/h), which is the maximum potential intensity a hurricane can reach today, and 233 mph (375 km/h) is definitely a possibility by the end of the century. hour) hurricane.
Milton Tampa Bay's worst-case scenario right now
Five of our top hurricane-specific forecast models—HWRF, HMON, HAFS-A, HAFS-B, and COAMPS-TC—already paint a very ugly picture for Tampa Bay of what Hurricane Milton could bring. In recent days, at least one run of all of these models has predicted that Milton will reach Cat 4 or Cat 5 intensity on Tuesday or Wednesday. Many routes show landfall north of Tampa Bay, which will maximize swells in the bay. However, many recent runs of these models predict that high wind shear and dry air will combine to disrupt Milton's core prior to landfall, causing it to rapidly weaken, possibly resulting in a Category 1 or 2 landfall. Unfortunately, such rapid weakening would spread the hurricane's strongest winds over a larger area, causing the damaging surge characteristics of a Category 3 hurricane to impact a wider swath of the coast. The most destructive scenario for Tampa Bay depicted by any model starting Sunday at 18Z (2 p.m. EDT) comes from the new HAFS-B model, which shows Milton traveling at 105 mph (170 kph) /hr) winds hit the large Cat 2 north of Tampa Bay (Figure 3). Such a storm could generate storm surges of more than 10 feet in the Gulf and cause more than $10 billion in damage. Last year, the HAFS-B model outperformed all other models in 3-day, 4-day and 5-day forecasts.
best case scenario so far Travel to Tampa Bay
The COAMPS-TC model run at 18Z (1 PM EDT) on October 6 depicts a plausible best-case scenario for Tampa Bay (Figure 4). The model describes Milton as a low-end Cat 3 making landfall about 80 miles south of Tampa Bay, near Fort Myers. However, Tampa's best-case scenario would be a nightmare for Southwest Florida, with losses that could exceed $10 billion.
Bottom line: Be prepared for the worst. My post 30 Excellent Tools for Determining Flood Risk in the United States is a good place to assess flood risk.
