Hurricane Dennis

This article is about the hurricane of 2005. For other storms of the same name, see Hurricane Dennis (disambiguation).

Hurricane Dennis was the fourth named storm, first hurricane, and first major hurricane of the 2005 Atlantic hurricane season. Dennis hit Cuba as a Category 4 storm and made landfall in the U.S. as a Category 3 storm between Pensacola Beach and Navarre Beach, Florida, at 2:25pm CDT (1925 UTC) on July 10, 2005.

Dennis set two records for early season activity, becoming both the earliest fourth named storm when it became a tropical storm on July 5, and the strongest storm ever to form prior to August (although that distinction was very short-lived, as Hurricane Emily took that record away just nine days later). It affected Haiti and Jamaica with high winds and heavy rain before hitting south-central Cuba at Category 4 intensity on July 8. As a comparison to the 2004 Atlantic hurricane season, Hurricane Alex formed in early August and Hurricane Charley made landfall in Cuba on August 12. It did briefly regain Category 4 status, but weakened to a Category 3 before making landfall due to cooler water along the coast.

Dennis caused at least 71 deaths in the United States and Caribbean, and caused $5-9 billion in damage, about half of it in the Caribbean. Damage was not as high as expected in the United States, mainly because Dennis was more compact and moved through quicker than initially forecast.

Storm history

Hurricane Dennis began as Tropical Depression Four in the southeastern Caribbean Sea on the evening of July 4, the first storm of the season to form away from Mexico and Central America. On the morning of July 5, it strengthened into Tropical Storm Dennis in the eastern Caribbean. The newly-named storm began moving rapidly to the west-northwest.

It was very clear from early weather forecasting models that Dennis had the potential to be a major storm, and it was predicted to reach hurricane status while it was still "Atlantic Tropical Depression Four". It reached hurricane strength on the afternoon of July 6 while approaching the southern coast of Hispaniola as a strong and well-organized Category 1 storm on the Saffir-Simpson Hurricane Scale. The next day it strengthened rapidly to become a Category 4 major hurricane, the earliest in the season that a storm has reached this strength since Hurricane Audrey in the 1957 season. Dennis's track became slightly more northerly, bringing it between Jamaica and Haiti on July 7.

As it approached Cuba and strengthened to just under Category 5 intensity, Dennis's track began to wobble. NHC meteorologists state that "this type of erratic motion is not unusual for intensifying major hurricanes." [1] Its wind speed of 150 mph had by then surpassed Audrey's maximum, and was the highest ever recorded for a storm earlier than August (a record that lasted just nine days). It slammed into south-central Cuba on July 8.

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Dennis weakened to Category 1 intensity from the effects of crossing the island. NHC forecasts, though, continued to point to the possibility of a return to Category 4 status, after convection had been re-established. This was borne out by Dennis's reintensification on the afternoon of July 9, which was so rapid that NHC forecasters described it as having occurred "at a rate that bordered on insane." [2]. The storm reached Category 4 intensity again on the morning of July 10 as it moved north-northwest towards the central Gulf Coast, which had seen Tropical Storm Arlene in June and Tropical Storm Cindy make landfall the previous week.

On the morning of July 10, hurricane warnings were in effect for the Florida Panhandle, Alabama and Mississippi, with tropical storm warnings extending further. The NHC predicted a landing at near full strength in the late afternoon. However, much like Hurricane Ivan, which struck in the same area the previous year, the storm weakened just before landfall, with its maximum sustained winds weakening from 145 mph (235 km/h, Category 4 strength) to 120 mph (195 km/h, Category 3 strength).

Landfall was made at Santa Rosa Island, between Pensacola, Florida and Navarre Beach, Florida, at 2:25 pm CDT (1925 UTC) on July 10. Dennis was a Category 3 hurricane with winds of 115 to 120 mph (185 to 195 km/h). The highest official wind speed reported was a 121 mph wind gust at Navarre Beach [3]. It lost strength over the day, and was a tropical depression by early on July 11. It persisted however, and gained a little strength while stalled over Illinois the next day. It finally dissipated on July 13, with advisories ceasing a full three days after landfall.

Preparations

In the United States, the lower Florida Keys were placed under a mandatory evacuation order, and a non-resident and mobile home resident evacuation was ordered for the remainder of the Keys. This evacuation was cancelled the night of July 8, as there was no longer sufficient time for stragglers in the Florida Keys to safely leave. Furthermore, the governors of Florida, Alabama, Mississippi and Louisiana all declared states of emergency in their states.

At 6 am CDT on July 9, 2005, all southbound lanes on Interstate 65 from Mobile, AL to Montgomery, AL were closed. Traffic was re-directed to all four lanes Northbound to allow evacuations. In Alabama, residents in all parts of Mobile County, and those south of I-10 in Baldwin County, were ordered to evacuate. Similar orders were issued in Mississippi for parts of Jackson, Hancock and Harrison counties; and for coastal areas in the Florida Panhandle, stretching from Escambia County to Bay County. Likewise, military installations, such as NAS Pensacola, Whiting Field, Eglin AFB, Hurlburt Field and Tyndall AFB, were all evacuated days before the storm.

In Cuba, more than 600,000 residents were moved from their homes to government shelters or other locations in anticipation of Dennis. [4] In Haiti, officials evacuated residents along the coastline, but noted that many were not obliging. [5]

Effects

Combined with Tropical Storm Cindy's landfall on the Gulf Coast of the United States, uncertainty over Dennis helped push oil prices to a record high of $61.28 a barrel on July 6 [6], and again to $61.50 on July 7 [7], although they dropped below $60 on July 8.

Insurers estimate that as of Monday, July 11, Hurricane Dennis had done $3-5 billion in insured damage. The final damage figure will likely come in between $5-9 billion since insured damage is generally about half of total damage. [8]

Caribbean

In Haiti, 44 deaths were reported, including 16 who were killed when a bridge collapsed during the hurricane. [9] Furthermore, more than one hundred were believed to be missing in Haiti. [10]

In Cuba, Hurricane Dennis left 16 people dead and $1.4 billion in damages when it roared through the island, flattening houses and downing trees and powerlines. Relayed reports from Cuban meteorologists stated that a gust up to 149 mph (239 km/h) was detected at Cienfuegos, 85% of the power lines were down and extensive damage to the communications infrastructure had occurred. Dennis was the worst hurricane to strike Cuba since Flora in 1963.

United States

During the height of the storm, Dennis left 680,000 customers without electricity in four southern states. No significant damage was reported to most structures, but insured damage from Dennis in the United States is estimated to have ranged from $1.25 to 2.5 billion [11]. Considering insured damage usually accounts for half of all damage, total damage in the United States is expected to range from $2-5 billion.

Dennis made landfall near where Hurricane Ivan had made landfall 10 months before, but did not cause as much damage as Ivan. Most officials were attributing the lessened damage to the facts that a) Dennis was moving about 7mph faster than Ivan was at landfall, and b) Dennis had hurricane-force winds that did not extend as far from the center as Ivan's did (40 miles versus 105 miles, respectively). [12] [13]

In the United States, 10 storm-related deaths were reported, including one in Walton County, Florida [14], two in Fort Lauderdale, Florida [15] and one in Decatur, Georgia. [16] In the Gulf of Mexico, the storm heavily damaged "Thunder Horse", a BP oil rig about 150 miles (240 km) southeast of New Orleans, Louisiana, causing it to list badly. [17]

On the other hand, one beneficial effect as a result of Hurricane Dennis was the rolling of the former USS Spiegel Grove. Spiegel Grove was sunk in Florida Keys National Marine Sanctuary as an attempt at creating an artificial reef. However, the ship turned turtle and landed on the bottom upside down. Efforts to roll the ship were partially successful, bringing it onto its starboard side, but Hurricane Dennis was able to complete the roll, bringing Spiegel Grove into its intended upright position.

Official forecasts

External links

NowPublic - Photographs and videos of Dennis.
Historic Images of Florida Hurricanes (State Archives of Florida )