Louisiana hurricane history - Part 2: 1856 Last Island hurricane (Aug 9 - Aug 12)

The "Last Island" hurricane of August 1856 was a particularly strong and destructive Category 4 hurricane, having attained 130 kt (150 mph) winds prior to its landfall in southeastern Louisiana at that intensity. This hurricane was unusual in that it became so strong during only the second week of August. The exact amount of deaths brought on by the hurricane are unknown, but is estimated anywhere between 200-400. The hurricane was so destructive that it caused the once resort known as Last Island to split into several small barrier islands, now known as Isle Dernieres.

Storm History

The origins of this hurricane is quite unclear, but it could have formed in one of two ways: a) from a complex interaction of several meteorological features over across the western Atlantic and adjacent Bahama Islands, a la Hurricane Katrina in 2005, or b) from a tropical wave that emerged from the west coast of Africa, formed into a Cape Verde hurricane in the far eastern Atlantic Ocean, and moved WNW across the Greater Antilles, a la Hurricane 5 during the exact same year. Regardless of the origin, it is clear that this hurricane's circulation had fully recovered from possible passage over the island(s) of the Greater Antilles, as evidenced by its rapid intensification from the morning of August 9, when it was first detected, (during which time it was located less than 150 miles WNW of the Dry Tortugas) up until its landfall late on the evening of August 10.

Initially, the hurricane moved steadily west-northwest. Eventually, however, the subtropical ridge collapsed somewhat, allowing for a northwesterly component of motion as the hurricane neared the coast. This northwestern turn occurred near noon on the 10th. During this time, the hurricane attained Category 4 status while centered less than 100 miles south of the Mouth of the Mississippi River. Also from this point onward, the forward speed of the hurricane gradually slowed as the ridge continued to steadily weaken with the approach of a shortwave trough to the west. Approximately twelve hours after attaining Category 4, the hurricane attained its estimated peak intensity of 150 mph and 934 mb (though, again, NOAA now suspects that the hurricane could have flirted with Category 5 status, meaning that it had winds of 155 mph, and I am inclined to agree with this -- quite strongly I might add, particularly due to the fact that the hurricane was still intensifying up until landfall, which implies that the friction from land interaction may have tightened up the circulation and deepened the convection within the eyewall both during and shortly after landfall) just as it made landfall between Cocodrie and Morgan City.

During the last two and a half days of its existence, namely when it was located at 27.7N 89.1W, the hurricane took a very similar path as 1992's Hurricane Andrew, owing to a very similar -- nearly identical, synoptic steering pattern, embedded between a trough to the west and a ridge to the east. After landfall, the devastating hurricane slowed to a crawl as it moved very slowly northwest, then northward across central Louisiana for nearly two days. The hurricane passed about 50 miles to the west of the capital city of Baton Rouge as a hurricane around noontime on the 11th. Finally, steering currents began to restrengthen in the early morning hours of August 12 as the aforementioned trough drew ever closer to the tropical cyclone, which was nearing southwestern Mississippi at this time. Shortly thereafter, the system officially ceased being tracked, though it is still estimated to have contained sustained winds of 45 kt (50 mph) during this time, and so it is likely that the system persisted for at least another twelve hours, and probably dissipated somewhere over eastern Mississippi.

Track

Figure 1. Track of the hurricane.

Impact

New Orleans received a staggering 13.14 inches of rain from the storm. Further west, the town of Abbeville, located in Vermilion Parish, was completely destroyed by the monstrous hurricane. Additionally, severe flooding was experienced throughout Plaquemines Parish.

On August 9, inhabitants on the island noticed a frightening roaring sound emanating from the Gulf of Mexico, which would soon turn very violent. During this time, cattle that were present on the island paced nervously back and forth for several hours, clearly sensing danger. Later that day, the skies darkened as torrential rainfall began to fall, with the slow-moving hurricane impacting the general area for two consecutive days. All 100 of the structures on Last Island was destroyed by the ferocious hurricane.

On August 10, tourists on the island noted the ferocity of the waves as the hurricane was approaching. Later on, a survivor, Rev. Robert McAllister, would write a rather frightening but simultaneously sobering excerpt on the destructive hurricane: "Each breaker extended to the right and left as far as the eye, straining its vision, could reach... We did not know then as we did afterwards that the voice of those many waters was solemnly saying to us, 'Escape for thy life."

One other interesting thing about this storm is the story of the tourists on the island attending a party at the hotel, while the hurricane drew ever closer, the winds outside steadily increasing. When the storm made landfall on the 10th, the conditions outside rapidly worsening, the aforementioned tourists anxiously awaited the arrival of the island's service steamer, labeled Star, but it failed to arrive in time. At around 4 AM on the morning of August 10, the hurricane's massive storm surge inundated the entire island, obliterating all of the structures present therein, including the multiple-story resort hotel. Star was grounded by the ferocious cyclone, although fortunately, a few people managed to survive by climbing aboard the now wrecked vessel.

After the event, Last Island was split into several small barrier islands, and these islands reportedly remained submerged for several days after the hurricane's passage, only to reappear as sandbars later. Subsequent to the powerful storm, the remains of the aforementioned vessel, Star, were the only evidence that an island had ever existed there. There were a total of 400 tourists on the island, but less than half survived the frightening storm.