When it comes to water, wind speed matters less than the size of the wind field. Ten years ago today, Hurricane Ike made landfall as "only" a Category 2 hurricane along Galveston Island near Houston. Though Ike had 110mph winds at landfall, it had grown very large over the Gulf of Mexico, and this large size allowed it to develop an enormous amount of "integrated energy" that manifested itself as a devastating storm surge. With about $30 billion in damages, Hurricane Ike was, at the time, the second-costliest US hurricane on record. As of Thursday morning, Hurricane Florence has weakened to 110 mph as it contends with slightly increased wind shear and drier air. Technically this means Florence is no longer a "major" hurricane, and it may not be when it reaches the North Carolina coast early on Friday morning. Practically, however, that won't matter when it comes to storm surge and inland rainfall. The simplest, most common metric for the measurement of a storm's intensity is maximum wind speed, and certainly this matters in terms of pure destructive potential when it comes to, say, losing a roof or propelling debris through the air. But when it comes to water, the maximum wind speed matters less than the size of the wind field for both storm surge and the destructive power of waves moving onshore. And Florence is a large storm, with hurricane-force winds extending outward up to 80 miles from the center and tropical-storm-force winds outward up to 195 miles. The primary example of this is 2012's Hurricane Sandy, which had modest 80mph winds by the time it reached the New York and New Jersey areas. But because the storm was so large it produced a destructive storm surge in New York City and caused an estimated $65 billion in damage in the United States. (At the time, it became the second costliest US hurricane but has since been supplanted by Harvey and Maria, both in 2017). Thursday, September 13th is the 10 year anniversary of Hurricane Ike. The storm's 15'+ surge devastated the Bolivar peninsula. The outer banks of North Carolina may face a similar threat from Florence. Our thoughts are with you Carolina. Prep for the worst, and hope for the best The area to the north of Florence's landfall along the North Carolina coast—storm surge is always worst to the "right" of a storm's center, where its rotation pushes water onshore—is less populated and developed than the New Jersey and New York shores. But the storm surge will be no less devastating for homes and businesses located there. Areas from Cape Fear to Cape Lookout face a potential 9 to 13 feet of storm surge, the National Hurricane Center warns, on top of the normal tides. Florence's slow movement over the next two or three days will add another element of uncertainty. Meteorologist Greg Diamond has noted that areas along the coast of North Carolina on the right side of the storm could experience a significant storm surge through multiple high tide cycles, which would have a cumulative battering effect. The National Hurricane Center has, accordingly, warned that "Life-threatening, catastrophic flash flooding and prolonged significant river flooding are likely over portions of the Carolinas and the southern and central Appalachians late this week into early next week, as Florence is expected to slow down as it approaches the coast and moves inland. " It is important to recognize that, while attention will be focused on coastal impacts from Florence, inland flooding will remain a problem for some areas well into next week.
A new video from The Weather Channel shows in real time the danger of flood waters already rising in parts of the Carolinas as Hurricane Florence starts battering the coast. The storm is moving slowly and is anticipated to bring deadly storm surges to the region as well as torrential rains. Thats a recipe for a flooding disaster, meteorologist Marshall Shepherd told The Verge in an interview on Monday. The National Hurricane Center is predicting storm surges anywhere from two to more than 11 feet high. But its hard to visualize what those numbers actually mean for someone near the water. The National Hurricane Center tried to make it clear with a cartoon graphic that shows rainbow colored water levels rising over the heads of a family in a house. You'll be seeing the NHC potential storm surge flooding graphic a lot over the next few days as #Florence nears the coast. Here's how to interpret it; The graphic is more effective than numbers, or even maps. But The Weather Channel takes the visuals a step further using mixed reality that show the waters surrounding the on-screen meteorologists, including Greg Postel and Ericka Navarro. The flood rises above their heads as the wind howls and floating cars slosh at the surface. This @weatherchannel visualization of storm surge is an amazing and sobering use of technology to show what hurricanes like Florence can do The mixed reality graphics, created in partnership with augmented reality company The Future Group, harness the Unreal Engine — a popular video game development platform. Rather than creating effects and rendering them in post-production, the process used to create visuals for most films, the Unreal Engine builds effects in real time, Ren LaForme reported for Poynter when The Weather Channel unveiled the tech in a tornado demo. The Weather Channel has since used the immersive reality for an in-studio lightning explainer, and now, to visualize Hurricane Florences floods. The business that were in is safety, Michael Potts, The Weather Channels vice president of design, told The Verge in an interview. The weather is a visceral, physical thing, and were trying to recreate that in the most realistic way possible. On screen, the water towers over the meteorologist as fish swim by — adding emphasis to her words that Hurricane Florences floods will threaten lives. If you find yourself here, please get out, she says. If youre told to go, you need to go.