Another Atlantic hurricane season is upon us starting on June 1st. What will this season bring? Hard to foretell, but some data can help us with the basics.
First of all, the good
Colorado State University released its forecast (usually the first out every year), which projects an Atlantic hurricane season somewhat weaker than recent years, with 13 named storms (winds of 39 mph or higher), six hurricanes (winds of 74 mph or higher), and two major hurricanes (Category 3, 4 or 5, with winds of 111 mph or higher).
The National Oceanic and Atmospheric Administration (NOAA) forecast, released on May 25, calls for similar numbers: 12 to 17 total named storms, of which 5 to 9 could become hurricanes, with 1 to 4 being major. NOAA has a 70% confidence in these ranges (but see more about uncertainty below).
This forecast is a bit different from (and note, better than) first forecasts for recent years:
- 2022: 14 to 21 named storms, with 6 to 10 hurricanes and 3 to 6 of those becoming major hurricanes;
- 2021: 15 to 21 named storms, with 7 to 10 becoming hurricanes, of which 3 to 5 could become major hurricanes;
- 2020: 19 to 25 named storms, with 7 to 11 turning into hurricanes, 3 to 6 of which would be major.
Another good fact is that 2023, like 2022, did not have a named storm form before the official season start, unlike the 7 straight years from 2015 to 2021.
The (maybe) bad
We certainly know there is usually quite some difference between the forecast and the real numbers at the end of each season. 2022 fortunately kept to the lower end of the forecast range with 14 named storms, eight hurricanes, and two major hurricanes. 2021 ended up being the third most active season in recorded history, with 21 named storms, 7 hurricanes, and 4 major hurricanes (two Category 3 and two Category 4). 2020 went well above the forecast, with a record 30 named storms, 14 of which turned into hurricanes, seven becoming major hurricanes. 2020 was also the second time in tropical storm naming history (after 2005) that the National Hurricane Center had to use the Greek alphabet letters to name storms after the regular list of names was exhausted.
These numbers show us that forecasts are useful but not binding—they come with an associated probability that those numbers will actually happen. NOAA stated that there is a “40% chance of a near-normal season, a 30% chance of an above-normal season and a 30% chance of a below-normal season.” We see from those numbers that the actual season can pretty much go anywhere—be near-normal, above-normal, or below normal. No wonder this year’s probability is said to have “larger-than-normal uncertainty,” likely linked to the uncertainty on El Niño formation and strength.
(Little bit of science behind forecasts)
These forecasts are based on some pretty standard measurements, monitored throughout the year, plus some relevant factors. Conditions behind this year’s forecasts are conducive to a somewhat below-average season. That is mainly due to a predicted development of an El Niño by late summer or early fall, which historically tampers down Atlantic tropical cyclone (i.e., tropical storms and hurricanes) activity.
Depending on how early and strongly an El Niño develops, updated forecasts (usually released throughout the season to account for changes in predicting variables) are likely to change substantially. However, if an El Niño does not develop soon or strongly enough, sea surface temperatures are already so high (similar to those of the record-breaking 2020 season) that 2023 may end up very busy.
The National Oceanic and Atmospheric Administration’s Climate Prediction Center said there is a high chance El Niño conditions will form between May and July, and a higher probability it will form by fall (80% to 90%). It also said there is a high chance that it will be a strong El Niño. However, overall, there is a large uncertainty in this year’s forecast. We wait.
The ugly
We know it takes only one hurricane making landfall to potentially have a huge impact. The fact that mean hurricane intensification rate has increased significantly along Atlantic coast over the last 40 years is a worrisome trend (this trend was not detected for the Gulf coast). Previous studies have also identified the trend of rapid intensification (see here and here).
A hurricane intensifying faster makes forecasts trickier, with less advance warning time, which leaves coastal communities and emergency responders with less time to prepare and react. This is particularly worrisome for communities that lack the resources to properly prepare and, if needed, evacuate. As mentioned on a previous blog I co-authored with my colleague Juan Declet-Barreto, it has been observed that disaster relief and recovery measures have lagged for Black, Latinx, and low-income people, and that communities of color receive less disaster relief and recovery funds than white communities.
The Colorado State University forecast report lists the following probabilities of major hurricanes making landfall:
• 44% for the entire US coastline
• 22% for the US East Coast including the Florida peninsula
• 28% for the Gulf Coast from the Florida panhandle westward to Brownsville
• 49% for the Caribbean
And there are other concerns
In addition to numbers and probabilities themselves, there are various other issues related to hurricanes and their impacts. Yale Climate Connections reported that, based on analyses from the National Hurricane Center, most hurricane-related deaths are not directly caused by storm surge or wind associated with the hurricane, but are due to carbon monoxide poisoning, electrocution, vehicle incidents, heat-related issues, and other indirect causes—many far from the coast, such as what happened in 2021 with the remnants of hurricane Ida. Something to keep in mind when preparing for a hurricane.
Also, a 2022 study of Florida residents has shown that repeated exposures to hurricanes were positively associated with post-traumatic stress symptoms, generalized worries, global distress, and functional impairment. The study covered exposures to hurricanes Irma and Michael, strong hurricanes which happened in successive years, and included direct and indirect exposures as well as exposure to media coverage of hurricane damages and potential hurricane threats. It showed that people did not “acclimate” to the impacts but rather the psychological symptoms accumulated and intensified, suggesting the potential for a mental health crisis.
All this to show that hurricane impacts go well beyond the physical and local. It is important for those working with disaster preparedness, relief and recovery—as well as decisionmakers—to account for all possible consequences that can affect not only socioeconomic and environmental aspects of an impacted community, but also individual people’s lives and livelihoods—which can linger for quite some time, so many may not have fully recovered before the next hurricane hits. This story has some examples of these lingering consequences, which many people don’t realize are there and need to be addressed.
And of course, because hurricanes are becoming stronger, wetter, slower, and more destructive, and all these trends have been linked to anthropogenic global warming, it is essential and urgent that nations transition away from fossil fuels and invest on renewable, clean energy. As I said before, nations must act now to reduce emissions and avoid the worst of climate change and its impacts, keeping communities safe, listening to the science, and safeguarding critical systems across the globe.