Satellites do not have the capability to directly measure wind speeds, so they make estimates based upon other observable variables, using instruments such as a scatterometer. Yes, that’s a real word. By these indirect estimates, Oscar had sustained winds between 48 mph and 63 mph (77 kph to 101 kph), which remains well below the threshold for a hurricane (74 mph, 119 kph).
The Air Force aircraft found sustained winds, in a tiny area to be sure, of 85 mph (137 kph). Hence, Hurricane Oscar.
How this happened
Oscar’s development shocked forecasters. There was only a modest indication from satellite imagery, as of Friday, that anything would form; and none of the major global models indicated development of any kind. It was thought that the area of low pressure would get swamped by vertical wind shear this weekend as it neared Cuba.
However, the tiny size of Oscar confounded those expectations. Weather models struggle with the development of small hurricanes, and this is largely because the micro-physics of the smallest storms occur below the resolution of these models. Additionally, tiny hurricanes organize much more quickly and efficiently.
In other words, small storms can more easily make quick changes. Which is what happened with Oscar. The storm will bring heavy rain and winds to the eastern half of Cuba on Sunday before it lifts to the northeast, and brings rainfall and some storm surge into the Bahamas early next week.
Colonized artificial reef structures could absorb the power of storms.
Credit: Kemter/Getty Images
On October 10, 2018, Tyndall Air Force Base on the Gulf of Mexico—a pillar of American air superiority—found itself under aerial attack. Hurricane Michael, first spotted as a Category 2 storm off the Florida coast, unexpectedly hulked up to a Category 5. Sustained winds of 155 miles per hour whipped into the base, flinging power poles, flipping F-22s, and totaling more than 200 buildings. The sole saving grace: Despite sitting on a peninsula, Tyndall avoided flood damage. Michael’s 9- to 14-foot storm surge swamped other parts of Florida. Tyndall’s main defense was luck.
That $5 billion disaster at Tyndall was just one of a mounting number of extreme-weather events that convinced the US Department of Defense that it needed new ideas to protect the 1,700 coastal bases it’s responsible for globally. As hurricanes Helene and Milton have just shown, beachfront residents face compounding threats from climate change, and the Pentagon is no exception. Rising oceans are chewing away the shore. Stronger storms are more capable of flooding land.
In response, Tyndall will later this month test a new way to protect shorelines from intensified waves and storm surges: a prototype artificial reef, designed by a team led by Rutgers University scientists. The 50-meter-wide array, made up of three chevron-shaped structures each weighing about 46,000 pounds, can take 70 percent of the oomph out of waves, according to tests. But this isn’t your grandaddy’s seawall. It’s specifically designed to be colonized by oysters, some of nature’s most effective wave-killers.
If researchers can optimize these creatures to work in tandem with new artificial structures placed at sea, they believe the resulting barriers can take 90 percent of the energy out of waves. David Bushek, who directs the Haskin Shellfish Research Laboratory at Rutgers, swears he’s not hoping for a megastorm to come and show what his team’s unit is made of. But he’s not not hoping for one. “Models are always imperfect. They’re always a replica of something,” he says. “They’re not the real thing.”
Playing defense Reefense
The project is one of three being developed under a $67.6 million program launched by the US government’s Defense Advanced Research Projects Agency, or Darpa. Cheekily called Reefense, the initiative is the Pentagon’s effort to test if “hybrid” reefs, combining manmade structures with oysters or corals, can perform as well as a good ol’ seawall. Darpa chose three research teams, all led by US universities, in 2022. After two years of intensive research and development, their prototypes are starting to go into the water, with Rutgers’ first up.
Today, the Pentagon protects its coastal assets much as civilians do: by hardening them. Common approaches involve armoring the shore with retaining walls or arranging heavy objects, like rocks or concrete blocks, in long rows. But hardscape structures come with tradeoffs. They deflect rather than absorb wave energy, so protecting one’s own shoreline means exposing someone else’s. They’re also static: As sea levels rise and storms get stronger, it’s getting easier for water to surmount these structures. This wears them down faster and demands constant, expensive repairs.
In recent decades, a new idea has emerged: using nature as infrastructure. Restoring coastal habitats like marshes and mangroves, it turns out, helps hold off waves and storms. “Instead of armoring, you’re using nature’s natural capacity to absorb wave energy,” says Donna Marie Bilkovic, a professor at the Virginia Institute for Marine Science. Darpa is particularly interested in two creatures whose numbers have been decimated by humans but which are terrific wave-breakers when allowed to thrive: oysters and corals.
Oysters are effective wave-killers because of how they grow. The bivalves pile onto each other in large, sturdy mounds. The resulting structure, unlike a smooth seawall, is replete with nooks, crannies, and convolutions. When a wave strikes, its energy gets diffused into these gaps, and further spent on the jagged, complex surfaces of the oysters. Also unlike a seawall, an oyster wall can grow. Oysters have been shown to be capable of building vertically at a rate that matches sea-level rise—which suggests they’ll retain some protective value against higher tides and stronger storms.
Today hundreds of human-tended oyster reefs, particularly on America’s Atlantic coast, use these principles to protect the shore. They take diverse approaches; some look much like natural reefs, while others have an artificial component. Some cultivate oysters for food, with coastal protection a nice co-benefit; others are built specifically to preserve shorelines. What’s missing amid all this experimentation, says Bilkovic, is systematic performance data—the kind that could validate which approaches are most effective and cost-effective. “Right now the innovation is outpacing the science,” she says. “We need to have some type of systematic monitoring of projects, so we can better understand where the techniques work the best. There just isn’t funding, frankly.”
Hybrid deployments
Rather than wait for the data needed to engineer the perfect reef, Darpa wants to rapidly innovate them through a burst of R&D. Reefense has given awardees five years to deploy hybrid reefs that take up to 90 percent of the energy out of waves, without costing significantly more than traditional solutions. The manmade component should block waves immediately. But it should be quickly enhanced by organisms that build, in months or years, a living structure that would take nature decades.
The Rutgers team has built its prototype out of 788 interlocked concrete modules, each 2 feet wide and ranging in height from 1 to 2 feet tall. They have a scalloped appearance, with shelves jutting in all directions. Internally, all these shelves are connected by holes.
A Darpa-funded team will install sea barriers, made of hundreds of concrete modules, near a Florida military base. The scalloped shape should not only dissipate wave energy but invite oysters to build their own structures.
What this means is that when a wave strikes this structure, it smashes into the internal geometry, swirls around, and exits with less energy. This effect alone weakens the wave by 70 percent, according to the US Army Corps of Engineers, which tested a scale model in a wave simulator in Mississippi. But the effect should only improve as oysters colonize the structure. Bushek and his team have tried to design the shelves with the right hardness, texture, and shading to entice them.
But the reef’s value would be diminished if, say, disease were to wipe the mollusks out. This is why Darpa has tasked Rutgers with also engineering oysters resistant to dermo, a protozoan that’s dogged Atlantic oysters for decades. Darpa prohibited them using genetic-modification techniques. But thanks to recent advances in genomics, the Rutgers team can rapidly identify individual oysters with disease-resistant traits. It exposes these oysters to dermo in a lab, and crossbreeds the survivors, producing hardier mollusks. Traditionally it takes about three years to breed a generation of oysters for better disease resistance; Bushek says his team has done it in one.
The tropics are a different story
Oysters may suit the DoD’s needs in temperate waters, but for bases in tropical climates, it’s coral that builds the best seawalls. Hawaii, for instance, enjoys the protection of “fringing” coral reefs that extend offshore for hundreds of yards in a gentle slope along the seabed. The colossal, complex, and porous character of this surface exhausts wave energy over long distances, says Ben Jones, an oceanographer for the Applied Research Laboratory at the University of Hawaii—and head of the university’s Reefense project. He said it’s not unusual to see ocean swells of 6 to 8 feet way offshore, while the water at the seashore laps gently.
A Marine base in Hawaii will test out a new approach to coastal protection inspired by local coral reefs: A forward barrier will take the first blows of the waves, and a scattering of pyramids will further weaken waves before they get to shore.
Inspired by this effect, Jones and a team of researchers are designing an array that they’ll deploy near a US Marine Corps base in Oahu whose shoreline is rapidly receding. While the final design isn’t set yet, the broad strokes are: It will feature two 50-meter-wide barriers laid in rows, backed by 20 pyramid-like obstacles. All of these are hollow, thin-walled structures with sloping profiles and lots of big holes. Waves that crash into them will lose energy by crawling up the sides, but two design aspects of the structure—the width of the holes and the thinness of the walls—will generate turbulence in the water, causing it to spin off more energy as heat.
The manmade structures in Hawaii will be studded with concrete domes meant to encourage coral colonization. Though at grave risk from global warming, coral reefs are thought to provide coastal-protection benefits worth billions of dollars.
In the team’s full vision, the units are bolstered by about a thousand small coral colonies. Jones’ group plans to cover the structures with concrete modules that are about 20 inches in diameter. These have grooves and crevices that offer perfect shelters for coral larvae. The team will initially implant them with lab-bred coral. But they’re also experimenting with enticements, like light and sound, that help attract coral larvae from the wild—the better to build a wall that nature, not the Pentagon, will tend.
A third Reefense team, led by scientists at the University of Miami, takes its inspiration from a different sort of coral. Its design has a three-tiered structure. The foundation is made of long, hexagonal logs punctured with large holes; atop it is a dense layer with smaller holes—“imagine a sponge made of concrete,” says Andrew Baker, director of the university’s Coral Reef Futures Lab and the Reefense team lead.
The team thinks these artificial components will soak up plenty of wave energy—but it’s a crest of elkhorn coral at the top that will finish the job. Native to Florida, the Bahamas, and the Caribbean, elkhorn like to build dense reefs in shallow-water areas with high-intensity waves. They don’t mind getting whacked by water because it helps them harvest food; this whacking keeps wave energy from getting to shore.
Disease has ravaged Florida’s elkhorn populations in recent decades, and now ocean heat waves are dealing further damage. But their critical condition has also motivated policymakers to pursue options to save this iconic state species—including Baker’s, which is to develop an elkhorn more rugged against disease, higher temperatures, and nastier waves. Under Reefense, Baker says, his lab has developed elkhorn with 1.5° to 2° Celsius more heat tolerance than their ancestors. They also claim to have boosted the heat thresholds of symbiotic algae—an existentially important occupant of any healthy reef—and cross-bred local elkhorn with those from Honduras, where reefs have mysteriously withstood scorching waters.
An unexpected permitting issue, though, will force the Miami team to exit Reefense in 2025, without building the test unit it hoped to deploy near a Florida naval base. The federal permitting authority wanted a pot of money set aside to uninstall the structure if needed; Darpa felt it couldn’t do that in a timely way, according to Baker. (Darpa told WIRED every Reefense project has unique permitting challenges, so the Miami team’s fate doesn’t necessarily speak to anything broader. Representatives for the other two Reefense projects said Baker’s issue hasn’t come up for them.)
Though his team’s work with Reefense is coming to a premature end, Baker says, he’s confident their innovations will get deployed elsewhere. He’s been working with Key Biscayne, an island village near Miami whose shorelines have been chewed up by storms. Roland Samimy, the village’s chief resilience and sustainability officer, says they spend millions of dollars every few years importing sand for their rapidly receding beaches. He’s eager to see if a hybrid structure, like the University of Miami design, could offer protection at far lower cost. “People are realizing their manmade structures aren’t as resilient as nature is,” he says.
Not just Darpa
By no means is Darpa the only one experimenting in these areas. Around the world, there are efforts tackling various pieces of the puzzle, like breeding coral for greater heat resistance, or combining coral and oysters with artificial reefs, or designing low-carbon concrete that makes building these structures less environmentally damaging. Bilkovic, of the Virginia Institute for Marine Science, says Reefense will be a success if it demonstrates better ways of doing things than the prevailing methods—and has the data to back this up. “I’m looking forward to seeing what their findings are,” she says. “They’re systematically assessing the effectiveness of the project. Those lessons learned can be translated to other areas, and if the techniques are effective and work well, they can easily be translated to other regions.”
As for Darpa, though the Reefense prototypes are just starting to go in the water, the work is just beginning. All of these first-generation units will be scrutinized—both by the research teams and independent government auditors—to see whether their real-world performance matches what was in the models. Reefense is scheduled to conclude with a final report to the DoD in 2027. It won’t have a “winner” per se; as the Pentagon has bases around the world, it’s likely these three projects will all produce learnings that are relevant elsewhere.
Although their client has the largest military budget in the world, the three Reefense teams have been asked to keep an eye on the economics. Darpa has asked that project costs “not greatly exceed” those of conventional solutions, and tasked government monitors with checking the teams’ math. Catherine Campbell, Reefense’s program manager at Darpa, says affordability doesn’t just make it more likely the Pentagon will employ the technology—but that civilians can, too.
“This isn’t something bespoke for the military… we need to be in line with those kinds of cost metrics [in the civilian sector],” Campbell said in an email. “And that gives it potential for commercialization.”
This story originally appeared on wired.com.
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Using this simulated data set, called IRIS, the researchers selected for those storms that made landfall along a track similar to that of Milton. Using these, they show that the warming climate has boosted the frequency of storms of Milton’s intensity by 40 percent. Correspondingly, the maximum wind speeds of similar storms have been boosted by about 10 percent. In Milton’s case, that means that, in the absence of climate change, it was likely to have made landfall as a Category 2 storm, rather than the Category 3 it actually was.
Rainfall
The lack of full meteorological data caused a problem when it came to analyzing Milton’s rainfall. The researchers ended up having to analyze rainfall more generally. They took four data sets that do track rainfall across these regions and tracked the link between extreme rainfall and the warming climate to estimate how much more often extreme events occur in a world that is now 1.3° C warmer than it was in pre-industrial times.
They focus on instances of extreme one-day rainfall within the June to November period, looking specifically at 1-in-10-year and 1-in-100-year events. Both of these produced similar results, suggesting that heavy one-day rainfalls are about twice as likely in today’s climates, and the most extreme of these are between 20 and 30 percent more intense.
These results came from three of the four data sets used, which produced largely similar results. The fourth dataset they used suggested a far stronger effect of climate change, but since it wasn’t consistent with the rest, these results weren’t used.
As with the Helene analysis, it’s worth noting that this work represents a specific snapshot in time along a long-term warming trajectory. In other words, it’s looking at the impact of 1.3° C of warming at a time when our emissions are nearly at the point where they commit us to at least 1.5° C of warming. And that will tilt the scales further in favor of extreme weather events like this.
The researchers identified two distinct events associated with Helene’s landfall. The first was its actual landfall along the Florida coast. The second was the intense rainfall on the North Carolina/Tennessee border. This rainfall came against a backdrop of previous heavy rain caused by a stalled cold front meeting moisture brought north by the fringes of the hurricane. These two regions were examined separately.
A changed climate
In these two regions, the influence of climate change is estimated to have caused a 10 percent increase in the intensity of the rainfall. That may not seem like much, but it adds up. Over both a two- and three-day window centered on the point of maximal rainfall, climate change is estimated to have increased rainfall along the Florida Coast by 40 percent. For the southern Appalachians, the boost in rainfall is estimated to have been 70 percent.
The probability of storms with the wind intensity of Helene hitting land near where it did is about a once-in-130-year event in the IRIS dataset. Climate change has altered that so it’s now expected to return about once every 50 years. The high sea surface temperatures that helped fuel Helene are estimated to have been made as much as 500 times more likely by our changed climate.
Overall, the researchers estimate that rain events like Helene’s landfall should now be expected about once every seven years, although the uncertainty is large (running from three to 25 years). For the Appalachian region, where rainfall events this severe don’t appear in our records, they are likely to now be a once-in-every-70-years event thanks to climate warming (with an uncertainty of between 20 and 3,000 years).
“Together, these findings show that climate change is enhancing conditions conducive to the most powerful hurricanes like Helene, with more intense rainfall totals and wind speeds,” the researchers behind the work conclude.
Enlarge/ Satellite image of Tropical Storm Debby on Sunday morning.
NOAA
As often happens during the month of July, the Atlantic tropics entered a lull after Hurricane Beryl struck Texas and short-lived Tropical Storm Chris moved into Mexico. But now, with African dust diminishing from the atmosphere and August well under way, the oceans have awoken.
Tropical Storm Debby formed this weekend, and according to forecasters with the National Hurricane Center, the system is likely to reach Category 1 hurricane status before making landfall along the coastal bend of western Florida on Monday.
As hurricanes go, this is not the most threatening storm the Sunshine State has seen in recent years. Yes, no one likes a hurricane, or the storm surge it brings. But Debby is likely to strike a relatively unpopulated area of Florida, venting much of its fury on preserves and wildlife areas. This won’t be pleasant by any means, but as hurricanes go this one should be fairly manageable from a wind and surge standpoint.
Major flood storm expected
But there is a far larger threat from Debby that will unfold well into next week over the southeastern United States—a major flood storm. Historic flooding is likely in areas of Florida, Georgia, and South Carolina.
Debby is motoring along to the north-northwest at a fairly good clip as of Sunday morning, at 13 mph. This is a fairly common path for hurricanes as they skirt around the edge of high-pressure systems. Then, when they gain a sufficient amount of latitude—as Debby is now doing—they turn poleward and eventually move toward the northeast.
Debby is expected to meander next week.
National Hurricane Center
And this is just what Debby is likely to do through about Monday. However, after this time it appears that high pressure building over the central Atlantic Ocean will strengthen enough to block an escape path for Debby to the northeast. Should this occur, it will bottle up the storm in the vicinity of the Georgia and Carolina coasts for two or three days.
There remains a lot of uncertainty about just where Debby will go after striking Florida. Most likely it crosses Georgia on Tuesday and, then its center may reemerge into the Atlantic Ocean. Regardless, its center will likely be near, or just offshore. From there it will be able to tap into very warm seas, in the vicinity of 83 to 85 degrees Fahrenheit.
In such a pattern, with a nearly stationary storm, rainfall bands can be continually replenished by moisture drawn in from the ocean. This produces intense tropical rainfall and “training” in which a band of rainfall more or less comes to rest over a given area, fed by offshore moisture.
Because we are still a few days from this pattern setting up, and due to the uncertainty in Debby’s path, we cannot say precisely where the heaviest rains will occur. However the Weather Prediction Center, the arm of the National Weather Service tasked with predicting rainfall amounts, is forecasting some pretty staggering totals for the period of now through Friday.
Enlarge/ Rainfall accumulation forecast for next week from NOAA.
WeatherBell
From Savannah, Georgia, north through Hilton Head Island and Charleston, South Carolina, the Weather Prediction Center is calling for accumulations of 20 to 25 inches, with higher totals possible in some areas. Moreover, it is possible that these high rainfall totals extend dozens of miles inland.
The African wave train gets rolling
Parts of Florida and North Carolina may also see extremely high rainfall totals over the next several days, due to the uncertainty in Debby’s motion.
And that is not all. As we get deeper into August, tropical waves are starting to fire off of the west coast of Africa. One of these is now approaching the Windward Islands, and should move into the Caribbean Sea next week. There, it has a chance of developing into a tropical storm, or more. This is likely the beginning of a period of frenetic activity characteristic of August, September, and the first half of October in the Atlantic tropics.
All of this is in line with expectations from forecasters for an exceptionally busy Atlantic hurricane season. This is due both to an anomalously warm Atlantic Ocean—seas fueled by climate change are at all-time highs in the modern era—and the imminent development of La Niña in the Pacific Ocean, which creates conditions favorable for the development of hurricanes in the Atlantic basin, which includes the Caribbean Sea and Gulf of Mexico.
Enlarge/ Why yes, that Starlink dish is precariously perched to get around tree obstructions.
Eric Berger
I’ll readily grant you that Houston might not be the most idyllic spot in the world. The summer heat is borderline unbearable. The humidity is super sticky. We don’t have mountains or pristine beaches—we have concrete.
But we also have a pretty amazing melting pot of culture, wonderful cuisine, lots of jobs, and upward mobility. Most of the year, I love living here. Houston is totally the opposite of, “It’s a nice place to visit, but you wouldn’t want to live there.” Houston is not a particularly nice place to visit, but you might just want to live here.
Except for the hurricanes.
Houston is the largest city in the United States to be highly vulnerable to hurricanes. At a latitude of 29.7 degrees, the city is solidly in the subtropics, and much of it is built within 25 to 50 miles of the Gulf of Mexico. Every summer, with increasing dread, we watch tropical systems develop over the Atlantic Ocean and then move into the Gulf.
For some meteorologists and armchair forecasters, tracking hurricanes is fulfilling work and a passionate hobby. For those of us who live near the water along the upper Texas coast, following the movements of these storms is gut-wrenching stuff. A few days before a potential landfall, I’ll find myself jolting awake in the middle of the night by the realization that new model data must be available. When you see a storm turning toward you, or intensifying, it’s psychologically difficult to process.
Beryl the Bad
It felt like we were watching Beryl forever. It formed into a tropical depression on June 28, became a hurricane the next day, and by June 30, it was a major hurricane storming into the Caribbean Sea. Beryl set all kinds of records for a hurricane in late June and early July. Put simply, we have never seen an Atlantic storm intensify so rapidly, or so much, this early in the hurricane season. Beryl behaved as if it were the peak of the Atlantic season, in September, rather than the beginning of July—normally a pretty sleepy time for Atlantic hurricane activity. I wrote about this for Ars Technica a week ago.
At the time, it looked as though the greater Houston area would be completely spared by Beryl, as the most reliable modeling data took the storm across the Yucatan Peninsula and into the southern Gulf of Mexico before a final landfall in northern Mexico. But over time, the forecast began to change, with the track moving steadily up the Texas coast.
I was at a dinner to celebrate the birthday of my cousin’s wife last Friday when I snuck a peek at my phone. It was about 7 pm local time. We were at a Mexican restaurant in Galveston, and I knew the latest operational run of the European model was about to come out. This was a mistake, as the model indicated a landfall about 80 miles south of Houston, which would bring the core of the storm’s strongest winds over Houston.
I had to fake joviality for the rest of the night, while feeling sick to my stomach.
Barreling inland
The truth is, Beryl could have been much worse. After weakening due to interaction with the Yucatan Peninsula on Friday, Beryl moved into the Gulf of Mexico just about when I was having that celebratory dinner on Friday evening. At that point, it was a strong tropical storm with 60 mph sustained winds. It had nearly two and a half days over open water to re-organize, and that seemed likely. Beryl had Saturday to shrug off dry air and was expected to intensify significantly on Sunday. It was due to make landfall on Monday morning.
The track for Beryl continued to look grim over the weekend—although its landfall would occur well south of Houston, Beryl’s track inland would bring its center and core of strongest winds over the most densely populated part of the city. However, we took some solace from a lack of serious intensification on Saturday and Sunday. Even at 10 pm local time on Sunday, less than six hours before Beryl’s landfall near Matagorda, it was still not a hurricane.
However, in those final hours Beryl did finally start to get organized in a serious way. We have seen this before as hurricanes start to run up on the Texas coast, where frictional effects from its outer bands aid intensification. In the last six hours Beryl intensified into a Category 1 hurricane, with 80-mph sustained winds. The eyewall of the storm closed, and Beryl was poised for rapid intensification. Then it ran aground.
Normally, as a hurricane traverses land it starts to weaken fairly quickly. But Beryl didn’t. Instead, the storm maintained much of its strength and bulldozed right into the heart of Houston with near hurricane-force sustained winds and higher gusts. I suspect what happened is that Beryl, beginning to deepen, had a ton of momentum at landfall, and it took time for interaction with land to reverse that momentum and begin slowing down its winds.
First the lights went out. Then the Internet soon followed. Except for storm chasers, hurricanes are miserable experiences. There is the torrential rainfall and rising water. But most ominous of all, at least for me, are the howling winds. When stronger gusts come through, even sturdily built houses shake. Trees whip around violently. It is such an uncontrolled, violent fury that one must endure. Losing a connection to the outside world magnifies one’s sense of helplessness.
In the end, Beryl knocked out power to about 2.5 million customers across the Houston region, including yours truly. Because broadband Internet service providers generally rely on these electricity services to deliver Internet, many customers lost connectivity. Even cell phone towers, reduced to batteries or small generators, were often only capable of delivering text and voice services.
