Ivan the Terrible|
by John LaCorte
NWS WFO CTP
Hurricane Ivan was a classic Cape Verde storm that moved off the west coast of Africa during the first days of September as a tropical wave. The storm intensified as it moved westward and was named Ivan early on the morning of September 3rd.
Ivan seems to have been destined for infamy almost from the onset when it intensified at an abnormally low latitude for Atlantic tropical cyclones. Most tropical storms prefer to form and intensify just north of 10 degrees latitude. Ivan strengthened in the area of 8 to 9 degrees latitude as it tracked through the warm tropical waters of the equatorial Atlantic. By midday on the 5th winds hit 85 mph, making Ivan the strongest tropical cyclone ever in the Atlantic basin at such a low latitude.
Ivan continued steadily westward and moved through the southern Windward islands, making a direct hit on the island of Grenada on the evening of September 7th with winds in excess of 130 mph. At least 70 people were killed on the island and it is estimated that 90 percent of the structures on the island were damaged or destroyed. A 17th century prison, still in use, was severely damaged allowing numerous inmates to escape.
Now a solid category 4 storm on the Saffir Simpson hurricane intensity scale, Ivan tracked relentlessly west-northwest across the Caribbean basin. It appeared to have the island of Jamaica in its crosshairs on the 11th when it veered slightly west passing just south of the island. While this spared the Jamaica a devastating direct hit, the island was still severely affected with deadly flooding and winds in excess of 140 mph. The death toll was estimated to be 15 from the storm on Jamaica.
While the last minute shift to the west undoubtedly spared Jamaica from what would have been far worse damage, the track kept Ivan over the warm waters of the Caribbean allowing it to strengthen to a category 5 storm for a time between the 11th and the 13th, just as it was approaching the Cayman Islands. Also spared a direct hit, the Caymans none the less suffered major damage from the now large and extremely dangerous hurricane.
From there Ivan tracked over open water between western Cuba and the Yucatan peninsula, taking aim at the US Gulf Coast. For the next two days Ivan maintained at least category 4 status as it moved north. The storm was now not only intense; it was extremely large affecting much of the eastern Gulf of Mexico. Interests from Louisiana to the Florida Keys watched closely with evacuations urged for large sections of the Gulf coast. Residents in Florida were especially concerned, having been recently devastated by Hurricanes Charley and Frances.
Ivan eventually made landfall early in the morning of September 16 as a category 4 or strong category 3 storm between Mobile Alabama and Pensacola Florida. Wind gusts in excess of 100 mph were common, with hurricane force winds affecting an area more than 100 miles wide as the storm roared ashore. Ivan then tracked northeastward, triggering dozens of tornadoes and causing widespread flooding from the southern Appalachians through much of the northeastern US.
In all, Ivan is being blamed for about 50 deaths in the United States, and about 70 altogether in the Caribbean. This will make the storm the biggest killer since Hurricane Floyd killed 56 (in the US) in 1999. It will also be the 5th deadliest storm in the US since 1960. The deadliest storm was the infamous Hurricane Camille in 1969, one of just 3 category 5 storms to hit the US since 1900. Camille killed 259 people.
The slow moving remnants of this once-powerful Hurricane moved up from a landfall on the Gulf Coast near Mobile and Pensacola to the Appalachian Mountains in Mid-September of 2004. The remnants - deep, tropical moisture and strong circulation - of the storm interacted with a cold front moving down from Canada. These two systems merged over Central Pennsylvania on Friday, the 17th of September.
The result was generally between 4 and 9 inches of rain across the region, although there were some local reports of over 13 inches of rain. Some locations (including State College, PA) set their all-time daily (24 hour) rainfall records on Friday.
The torrential rains of Ivan followed one of the wettest summers on record for the region, and almost on the heels of heavy rainfall one week earlier from the remnants of former Hurricane Frances.
The flooding that resulted will go down in history as one of the worst flooding episodes in Central Pennsylvania. River Crests at two locations, Williamsburg, PA, on the Frankstown Branch of the Juniata River, and Beech Creek, PA, on the Bald Eagle Creek, both set new high water marks during this weekend. Water levels had never before been recorded so high at both those locations. Many other River Gages reached into the top-five crests of all-time.