A 23-foot robotic boat sailing straight into a Category 4 hurricane while all other ships on Earth are heading in the opposite direction is subtly amazing. No crew, no hesitation, no instinct to protect oneself. Simply sensors, a strengthened wing, and a massive volume of data returning to scientists on land. This is precisely what Saildrone has been doing since 2021, and this summer, the company is going out once more in collaboration with NOAA for the fifth year in a row.
During the height of Atlantic hurricane season, which runs from August to November, ten Saildrone Explorer unmanned surface vehicles will be deployed. They will disperse throughout the Caribbean Sea, the Gulf of America, and the western tropical and subtropical Atlantic, essentially waiting for problems to arise. The ships will move in the direction of storms rather than away from them. Every maritime instinct that has been developed over centuries of seafaring is oddly inverted.
Every Explorer is designed to withstand this type of penalty. The wing, which has been shortened for hurricane conditions, is designed to withstand sustained winds exceeding 110 miles per hour and seas exceeding 50 feet. The hull is 23 feet long. These thresholds are not theoretical. The drones have already experienced Hurricanes Ian, Milton, and Helene. Explorer SD-1083, which recorded footage close to Helene’s eyewall in wind gusts of up to 85 knots and waves pushing 52 feet, produced one of the most striking photos from the 2024 season. It seems almost unbelievable that it survived and continued to transmit.
The type of surface-level oceanic data that was previously lacking is what the drones gather. Global forecast centers receive real-time data on wind speed and direction, air temperature, sea surface temperature, barometric pressure, salinity, humidity, wave height, and period. Additionally, two of this season’s vehicles will have carbon dioxide sensors that track the exchange of gases between the atmosphere and the ocean. One of the project’s principal investigators, NOAA oceanographer Greg Foltz, has noted that each storm the fleet encounters adds a new layer to the prediction models. Longer warning windows and, eventually, fewer fatalities when storms approach coastlines are anticipated as a result of improved models.
One of the more challenging issues in storm forecasting is rapid intensification, which is the phenomenon where a hurricane intensifies significantly in a brief period of time. It’s the kind of situation that suddenly transforms a manageable Category 2 into a catastrophic Category 4, taking coastal communities by surprise. The precise exchange of heat and moisture that feeds the storm from below at the ocean’s surface frequently accounts for the knowledge gap. Saildrone and NOAA are working to bridge that exact gap.
The fleet has spent over 2,600 days at sea on this mission alone, intercepting 21 named hurricanes and tropical storms on 46 different occasions over the course of five years. Though it’s difficult to ignore the scale of what’s been constructed here, the numbers add up quietly and without much fanfare. Five cars in 2021, seven in 2022, and twelve in each of 2023 and 2024. Ten is coming up this year, and it seems like the program has settled into a routine.
Since science advances at its own pace, it is still unclear how long it will take for this data to result in quantifiable improvements in public forecasting. However, the infrastructure has been strengthened by dozens of actual storms and five hurricane seasons. This August, a tiny orange drone will tilt into 40-foot waves in the Atlantic and continue to transmit signals. There won’t be anyone on board to observe. In any case, the data will be delivered.
