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. Storms with broad circulations also create a greater amount of surge than smaller storms.

KCC's RiskInsight platform, which was recently updated to include storm surge flooding, provides detailed, high-resolution elevation data and can be used to identify areas and properties likely to be impacted by storm surge. RiskInsight estimates $300 billion of property value in Sandy's flood footprint and nearly $50 billion of flood damage to properties.

Future storms could prove much more damaging than Superstorm Sandy. For 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. The storm surge heights would be similar, although in different locations, with the most significant inundations along the coasts of eastern Long Island, Connecticut, Rhode Island and southern Massachusetts. RiskInsight estimates a repeat of the 1938 storm would cause flooding and wind damages totaling over $100 billion.

“Sandy's large size and right-angle approach to the coastline greatly enhanced the storm surge,” said Clark. “Had Sandy followed a more typical path parallel to the coast, the surge would have been much less, particularly in New Jersey, Staten Island, and Queens. Given Sandy's unusual characteristics, the likelihood of such a storm occurring again is very low, but future storms following more probable tracks and causing more extensive damage are much more likely.”

Sandy's unusual track was due primarily to the position of the jet stream. Some scientists have speculated that climate change is weakening the jet stream and increasing its tendency to meander. A climate scientist at Rutgers University has suggested the northward swings in the jet stream, like the one that existed at the time of Sandy, are happening more frequently, and that one month before Sandy, the Arctic sea ice extent reached a record low. That said, scientists generally agree that a direct link can't be made between low sea ice and Sandy's track. There is however widespread agreement that continuing sea level rise contributed to the significant storm surge damage from Sandy.

“The current scientific consensus is that climate change is not likely to produce more tropical cyclones but might in fact result in fewer but more intense storms,” said Ms. Clark. “That said, flooding damage from all types of storms will be exacerbated as ocean levels continue to rise.”

“Sandy has heightened awareness of the threat of the hurricane hazard in regions where the historical frequency has been low,” said Ms. 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. While Sandy was devastating to many coastal communities, there have been positive outcomes such as increased dialogue at the local, state and federal level on coastal hazards and how to mitigate the impacts of future storms.”

“We are very pleased to extend the RiskInsight platform to include storm surge flooding,” added Ms. Clark. “We have seen increased demand for this offering from insurances companies because insurers realize that only with the complete transparency that RiskInsight provides can they fully understand the risk and feel confident in their pricing and risk management decisions.”