Last night time, Tropical Storm Idalia strengthened into Hurricane Idalia, charting a course for Florida’s west coast and panhandle. Its most sustained winds have already reached practically 100 miles per hour, and it’s anticipated to maintain feeding on exceptionally heat ocean waters and intensifying earlier than making landfall early Wednesday. 

It will pound Florida—together with closely populated Tampa Bay—with a trifecta of compounding hazards: excessive winds, pouring rains, and an enormous storm surge, which may attain as much as 15 feet. The National Hurricane Center expects that “life-threatening” surge to deliver “catastrophic impacts.” 

While most individuals perceive {that a} hurricane brings wind and rain, the storm surge component is what causes excessive hazard to coastal communities. That’s what occurs when a storm turns into a large, swirling bulldozer that pushes a wall of water towards the shore. “The whole Gulf Coast of Florida—peninsula and panhandle—is one of the most storm-surge-vulnerable areas of the United States, or even the world,” says Rick Knabb, a hurricane knowledgeable on the Weather Channel and former director of the National Hurricane Center. “The only way to ensure you survive a storm surge—especially a catastrophic storm surge, which is what we’re expecting in the Florida Big Bend and Apalachee Bay tomorrow morning—is to not be there when it happens.”

Any hurricane feeds on heat water: Warm, moist air rises off the ocean floor, sending power into the environment. That moisture condenses into clouds and thunderstorms and releases its latent warmth, warming the core of the storm. That in flip lowers air stress, which will increase winds, which will increase how a lot water the system can evaporate off the ocean. 

Idalia has been feeding on hovering ocean temperatures. “It’s a machine that increasingly takes advantage of an increasing amount of heat and moisture that it’s extracting from the ocean,” says Knabb. “Temperatures are way up into the 80s and near 90 degrees in many parts of the eastern Gulf of Mexico. The Gulf is always warm enough to support hurricanes, but this year is way warmer than average, and in many locations at record levels.”

In basic, local weather change is dramatically warming the world’s oceans, providing fuel for extra-powerful hurricanes. But atmospheric dynamics are at play, too: Trade winds have been sluggish recently within the tropical Atlantic and throughout the Caribbean. Those winds would sometimes churn up deeper, cooler waters. But with much less of that upwelling, the waters within the Caribbean and round Florida have been heating like a pot on sluggish boil. “All of that has been festering for weeks and weeks,” Knabb says. “And now those waters are being used by this hurricane to fuel it.”

As Idalia chugs towards Florida, its winds are pushing a column of saltwater towards shore. The stronger the winds, the upper the water will likely be. The hurricane’s low stress can be making a type of offshore dome of water centered underneath the storm. The water rises as a result of there’s much less atmospheric stress on the ocean there. “That dome peaks right under the eye, where you have very low pressure,” says Brian McNoldy, a hurricane researcher on the University of Miami. “When the hurricane makes landfall, that dome of ocean water comes along with it.”