Hurricanes: Threats, Vulnerabilities, Consequences


The National Oceanic and Atmospheric Administration forecasts, “a range of 17 to 25 total named storms (winds of 39 mph or higher). Of those, 8 to 13 are forecast to become hurricanes (winds of 74 mph or higher), including 4 to 7 major hurricanes (category 3, 4 or 5; with winds of 111 mph or higher). Forecasters have a 70% confidence in these ranges. The upcoming Atlantic hurricane season is expected to have above-normal activity due to a confluence of factors, including near-record warm ocean temperatures in the Atlantic Ocean, development of La Nina conditions in the Pacific, reduced Atlantic trade winds and less wind shear, all of which tend to favor tropical storm formation.” A less active season has been forecast for the Central and Eastern Pacific.

More Atlantic hurricanes overall, more hurricanes at Category 3 and above, and an extended season increase the chances for landfalls with significant impacts on people. The risk of serious population impacts is also increasing as hurricanes are more likely to demonstrate rapid intensification. According to a 2023 report in Nature:

Quickly intensifying tropical cyclones (TCs) are exceptionally hazardous for Atlantic coastlines… Mean maximum TC intensification rates are up to 28.7% greater in a modern era (2001–2020) compared to a historical era (1971–1990). In the modern era, it is about as likely for TCs to intensify by at least 50 kts in 24 h, and more likely for TCs to intensify by at least 20 kts within 24 h than it was for TCs to intensify by these amounts in 36 h in the historical era. Finally, the number of TCs that intensify from a Category 1 hurricane (or weaker) into a major hurricane within 36 h has more than doubled in the modern era relative to the historical era. (More and more.)

Rapid intensification — especially near-shore intensification — can subvert evacuation plans and timing, potentially leaving more people in harms way. Many of the atmospheric factors that result in rapid intensification can also challenge the accuracy of forecast tracks (here and here and here). Threat assessment mostly tries to measure what will be hit when and how hard. Hurricane targets and intensities can be reasonably anticipated, but are tough to precisely predict.

Secondary effects of hurricane impacts — such as storm surge, flooding, and grid outages — interact with network vulnerabilities (see below) to amplify the hurricane threat. The NERC summer reliability assessment for the 2024 grid is a bit more robust, potentially resilient, than in recent years (more). But this summer’s heat forecast is also more robust. National Public Radio reports, “2023 was the hottest year on record for many places in the U.S., and by far the hottest year for the planet as a whole… It’s already been so hot that 2024 is guaranteed to be one of the five hottest years ever recorded.” One nightmare scenario is a hurricane-related grid loss followed by extended extreme heat descending on hard-hit survivors.


Despite recurring and increasing threats, the population growth of coastal communities has accelerated. Over 60 million people reside in Atlantic and Gulf Coast areas with hurricane histories. In recent years the population growth rate of these areas has often been more than ten percent higher than the national average (here).

Fixed assets are more vulnerable than mobile assets. Surface freight capacity is structurally and spatially diversified. Many freight assets — both drivers and trucks — are proactively relocated out of the way of hurricanes. Concentrated fuel capacity, such as refineries, pipelines, ports, and fuel racks stay put (see map below and here). As long as hurricanes stay away, fixed fuel capacity is okay. But if hurricanes hit fuel capacity concentrations hard enough to cause time-extended disruption or serious destruction, the network consequences can quickly cascade. Surface freight capacity depends on refueling. No fuel, no freight. In case of hurricane related grid loss many key supply chain components — such as public water systems and grocery distribution centers — depend on diesel-fueled emergency generators. No fuel = no emergency power = suddenly diminished flows of water and food = thirst and hunger.

This morning FreightWaves gives us a meaningful snapshot of current national freight capacity (see chart below):

Outbound tender volumes (OTVI) surged over 7.1% from May 26 to June 3, marking one of the strongest demand increases to start the summer shipping season since 2019. The spike in tender volume appears to have helped sustain spot rates, excluding estimated fuel costs (NTIL) at relatively elevated levels beyond the Memorial Day holiday period. Volumes tend to jump this time of the year, increasing between 0.3% and 6.8% over the past four years, but they jumped 8.8% in 2019, a time of a historically down market.  So while the tender volume jump was the largest in several years, it has not pushed rates higher proportionally — it has sustained the level. The reason for this lack of rate jump is largely that there is still enough capacity to handle it.

During the second half of 2023 US trucking capacity experienced a considerable contraction (here and here) adjusting to post-pandemic demand patterns. Still, freight capacity for the 2024 hurricane season is roughly the same as last year. In terms of truck transportation employee counts May 2024 is a bit higher than May 2019 or any prior May in the census records (more and more). As of the beginning of hurricane season, diesel fuel stocks are higher than the last two years. East Coast (PADD-1) diesel inventories are at least one-fifth higher than May 2022 or 2023. Gulf Coast (PADD-3) diesel stocks are also within or slightly above seasonal averages.


Risk is a function of what and how many are hit when (and again) and how hard. In the last week of September 2022 Hurricane Ian presented a serious threat to the Gulf Coast of Florida. Even one day before landfall Tampa Bay seemed to be the target. But instead, the high end CAT4 storm came ashore just north of Fort Myers (about 100 miles south of Tampa). Death and destruction was horrible. But this late right hand swerve saved the Tampa port, racks, and pipelines to fuel the response for Fort Myers, Cape Coral, and nearby. The cluster of food distribution centers between Tampa and Orlando (and near Miami) continued to direct flow into Southwest Florida. Because the midstream capacity concentrations were not hit, flow continued downstream to concentrations of demand. The harder the hit upstream the more disruption (or worse) downstream. Two years later I start this hurricane season especially attentive to threats that may unfold to food, fuel, and freight capacities concentrated near Tampa, Miami, Jacksonville/San Juan, and then near New Orleans, and then between Beaumont and Houston. If these capacity concentrations survive, consequences can be mitigated. The harder these critical nodes are hit, the more risk is amplified.