The unusual track of Superstorm Sandy makes the likelihood of such a storm occurring again very low, but future Northeast storms following more probable tracks could cause much far more damage, according to a catastrophe risk expert.
As an example, the Great New England Hurricane of 1938, if it were to happen today, would likely cause insured losses at least twice those of Sandy, notes Karen Clark, president of Karen Clark & Company (KCC) in a report published earlier this week. Based on the KCC’s RiskInsight model, the company estimates that a repeat of the 1938 storm would cause flooding and wind damages totaling over $100 billion.
The storm surge heights would be similar, although in different locations, the report says, noting that the resulting flooding damage would likely exceed $60 billion today—a figure which is comparable to Sandy.
In addition, a storm like the 1938 hurricane would cause would probably cause wind damages of $35 billion–much great than Sandy’s wind damage because of the significantly high wind speeds.
“While not the most expensive storm to impact the U.S. coastline, Sandy was the most costly borderline Category 1/tropical storm to make landfall in the historical record,” Clark said, in a statement about the report. “A rare combination of several meteorological phenomena occurred as Sandy was moving up the East Coast resulting in its unusual track. This path, combined with the storm’s immense size resulted in damages much greater than expected for such a weak hurricane,” said Clark, who is recognized as the founder of the first catastrophe modeling firm.
Clark said the Northeast United States is particularly vulnerable to storm surge given its relatively shallow coastal waters, presence of inlets, bays and rivers, and local topography.
In addition, a storm that makes landfall perpendicular to the coastline—as Sandy did—will produce a higher surge than the same storm moving parallel to the coast or coming ashore at a different angle.
Since 1900, the only other hurricane to directly hit New Jersey was the Vagabond Hurricane of 1903. KCC estimates that the 1903 event would cause only $3 billion in insured losses today—much less than Sandy. The 1903 hurricane was a weak Category 1 storm like Sandy, but it was much smaller and covered less area. It also had a more typical track—closer to parallel to the coast
Sandy’s unusual track was due primarily to the position of the jet stream, according to the KCC report, which also notes that some scientists have speculated that climate change is weakening the jet stream and increasing its tendency to meander.
“Sandy has heightened awareness of the threat of the hurricane hazard in regions where the historical frequency has been low,” said Clark. “Sandy clearly demonstrates that even weak tropical systems can cause tremendous damage in the Northeast, primarily because storms tend to be large in this region and there are such high concentrations of property values.”
Providing further information on the 1938 event, which had a more usual track, the KCC report said it is estimated to have been a Category 3 storm at landfall on Bellport, Long Island with peak sustained winds of 120 mph.
The track of the 1938 hurricane would generate the highest storm surge along eastern Long Island, Connecticut, Rhode Island and southern Massachusetts, the KCC report notes, adding that Narragansett Bay poses the largest threat “because of how the funneling effect impacts the city of Providence.” In 1938, Providence was submerged under 20 feet of water, but a storm barrier constructed in the 1960s lessened damage from subsequent storms.
Source: Karen Clark & Company