“It’s very simple,” Glenn says. “If the ocean’s warm, it increases intensity. If the ocean’s cool, it decreases intensity. So if you want to get the intensity right, you have to get the ocean right.”

If Glenn is correct, and data like his can be made available to meteorologists and researchers in a timely way, it could dramatically improve the accuracy of hurricane-intensity forecasting, which has barely budged in recent years even as track forecasting has gotten better by orders of magnitude. It could also benefit emergency agencies, particularly in cases where residents have ignored warnings because previous forecasts were overblown.

Read: Modern weather forecasts are stunningly accurate

“It makes all the sense in the world,” says Jennifer Francis, a senior scientist at the Woods Hole Research Center in Massachusetts who specializes in Arctic climate change and how that affects weather patterns in the middle latitudes. Until recently, Francis worked in the same department as Glenn at Rutgers, but she conducted no joint research with him.

“This really key factor is probably going to offer a big step forward in doing a better job with intensity forecasting,” Francis said.

Until drone gliders came along, forecasters had no way of knowing what was going on below the ocean surface during a storm. Unlike the hurricane-hunter aircraft that fly into and around storms, it’s too dangerous to leave ships in their path to take measurements. And satellites—which can measure surface temperatures only under the best of conditions—can’t detect anything through storm clouds.

Glenn and other ocean researchers have been using underwater gliders since around the turn of the millennium, recording data such as temperature and salinity over deep and large areas not otherwise easily accessible. The gliders have no engines. They use a battery to operate a pump system that sucks in water to shift weight to make them move up and down in the water at about half a mile an hour. An inflatable bladder allows the tail of the glider to surface and transmit some of its information by satellite, making it readable in close to real time on monitors virtually anywhere. The battery also operates the glider’s computer, instruments, and satellite communications, and can last for months.

At the time of Irene’s approach, Glenn was measuring water quality when he decided to leave his glider in place to collect further readings during the storm. His data, which weren’t fully analyzed until afterward, showed the water temperature dropped 6 to 11 degrees Celsius in the hours before Irene’s eye passed through. “We saw that there was a big change,” says Glenn, a distinguished professor in the Department of Marine and Coastal Sciences and co-director of the Center for Ocean Observing Leadership at Rutgers.