Do you know what the most threatening part of a hurricane is?

The answer to that question might be shocking to some, and has proven to be deadly to others. Storm Surge.  Storm surge is an abnormal rise of water generated by a storm, over and above the predicted astronomical tides. Storm surge in the Atlantic, especially in the Gulf of Mexico, is the greatest threat to life and property because of its power.

Measure

Although storm surge was recently taken out of the Saffir Simpson scale, new measures are being developed by meteorologists to relate the strength of storm surge to the strength and size of the storms as well as the shape of the coastline. One of these new measures, called Integrated Kinetic Energy and developed by the Atlantic Oceanographic & Meteorological Laboratory in Miami, FL, connects all of those aspects and simplifies all of that science down to a 0-6 scale that is easier to understand. Storms with an IKE of 0.1 have virtually no surge while storms with an IKE of larger than 5 are extremely destructive. Hurricane Ike, coincidentally named, had an IKE of 5.6 had a surge of more than 18 feet above astronomical tide. I will be talking about this measure as hurricane season begins as I think this is the scale of the future.

One very common myth with storm surge is that the Saffir Simpson category relates directly to storm surge. This is absolutely FALSE. For instance, Hurricane Ike was only a category 2 and Hurricane Sandy was very likely a 6. Those two storms were not major hurricanes. Hurricane Charley in 2004 was a category 4 on the Saffir Simpson hurricane wind scale, but only produced 7 feet of storm surge.  Charley likely would have been rated around or less than 2.0, but was not rated since that scale was not created until after Charley.

Point #1: FEMA Administrator has been quoted in saying “There is more to the Story than the Category”…and that is a story to stick to an remember.

Video #1: A 90 second video with an overview of storm surge from the National Hurricane Center: http://youtu.be/84VFVZS04hM

Know YOUR Zone

Unlike winds in a hurricane, the most intense storms surge can occur hundreds of miles away from the center of a hurricane. As we found out with Hurricane Sandy, surge is not just an issue related to the ocean. It also can build up on lakes and rivers. In some hurricanes in the past, the Mississippi River has been stopped in its tracks and has even been forced to flow backwards! In Sandy, waves and water built up along Lake Shore Drive near downtown Chicago which was more than 700 miles away!

Surge can also drive inland along smaller creeks and rivers up to 50 miles. This is the case across the mid-Atlantic and in the northeastern Gulf of Mexico. It is ever more important to know your evacuation zone. To find out exactly what your zone is go to google and type in “Evacuation Zone”, which will take you do your county’s zone map. It is even more important to evacuate your zone if local authorities

Point #2: Even if you looked up your zone last year, you need to check it again. Zones can change from year to year as technology and models evolve. 

Video #2: An in-depth look at storm surge and it’s impacts to each and every one of us: http://youtu.be/AUveZWKyeyw

The Focus

Storm surge will be the focus of the season for many meteorologists because of the power and destructiveness that it contains. In fact, the National Hurricane Center is taking such a stab at this particular aspect of hurricanes that an entirely new suite of products is being developed. This year, the NHC is refocusing it’s forecasts to be probabilistic. The analogy to this is when your local meteorologist says there is a 60% chance of rain for your area. This product will give the coastal areas a certain chance of inundation above ground level and by how much. For instance, hurricane A has a 30% chance of inundating area T with 4 feet of storm surge within 48 hours.

Point #3: Don’t take the ocean lightly. If you live within 100 miles of any body of water, it may come a lot closer if a hurricane is forecast near your area. 

For an entire in-depth look at surge, you can go to:

The NHC’s Storm Surge Page: http://www.nhc.noaa.gov/surge/

NWS Tallahassee’s Storm Surge Page: http://www.srh.noaa.gov/news/display_cmsstory.php?wfo=tae&storyid=94265&source=0

Current Weather Note: It looks like the tropics are showing signs of awakening in the Atlantic, and the second depression of the season may form in the Pacific overnight. I’ll be taking a look at the situation later this week. See you then!

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Posted on Monday, May 27th, 2013, in Tropical Weather. Bookmark the permalink. Leave a comment.

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