Hurricane’s feared ‘storm surge’ will now get its own set of alerts
Mound of water that washes ashore is the deadliest event
Storm surge — the deadliest threat from hurricanes — will get its own set of alerts for the first time when the season officially starts Thursday, the National Weather Service said.
Storm surge is the massive mound of water that builds up and comes ashore as a hurricane moves over the Atlantic Ocean or Gulf of Mexico. It has accounted for about half of hurricane deaths since 1970, the National Hurricane Center said. Storm surge caused most of the 1,200 deaths when Hurricane Katrina struck the Gulf Coast in 2005.
Storm surge watches and warnings will be separate from hurricane alerts because hurricane-force winds and storm surg- es don’t always occur at the same place or the same time, said Rick Knabb, former director of the hurricane center and now an expert at the Weather Channel.
In addition, preparing for hurricane-force winds is different than for storm surge, he said. For storm surge, people should evacuate, while for wind, they can stay in place in a strong structure as long as it’s away from flood-prone areas, Knabb said.
A “storm surge watch” will be issued when flooding is possible, and a “warning ” will be issued when flooding is expected. Every city along the Gulf Coast or East Coast is at risk of storm surge, the hurricane center said.
In addition to being the deadliest threat, surge is also typically the most destructive part of a hurricane. When Hurricane Sandy hit in 2012, storm surge-induced flooding measured as high as 9 feet above ground in parts of New York and New Jersey, leading to billions of dollars in damage.
The damage occurred even though Sandy spun ashore as the equivalent of only a Category 1 hurricane, with winds of about 80 mph, and was downgraded below hurricane status shortly thereafter.
Storm surge flooding does not include floods caused by the heavy rain from the hurricane, such as what happened in North Carolina last year during Hurricane Matthew. It also has nothing to do with tsunamis, large ocean waves generated by offshore earthquakes that are not related to weather.
Also new for this year: Meteorologists will begin issuing “potential tropical cyclone” watches, warnings and advisories for dis- turbances that could threaten land within 48 hours. “You might see our advisories a little sooner for something trying to form on our doorstep,” Knabb said.
Another update: The size of the cone of uncertainty, which has been steadily shrinking each year in the weather service’s track forecast graphic, is going to get a little smaller again. “We continue to get a little bit better every year with our track forecasting,” Knabb said.
Still, he said, people should focus more on the storm’s potential hazards than on the center of its track or the forecast cone.
NOAA predicts an unusually active 2017 hurricane season for the Atlantic Basin, with five to nine hurricanes expected to form before the season ends Nov. 30. One tropical storm already formed in the Atlantic: Arlene, which spun harmlessly in the middle of the ocean in April.
The next named storms will be Bret, Cindy, Don, Emily, Franklin and Gert.
For the first time, storm surges will get their own official watches and warnings separate from hurricane alerts.