Hurricane Isaac
8/30/2012 11:30:00 PM
Type of postingPosting date:time ESTSummaryScenariosDownloads
Post Landfall 18/30/2012 11:30:00 PM
Landfall 8/29/2012 1:50:00 PM
Pre-Landfall 78/28/2012 1:00:00 PM
Pre-Landfall 68/27/2012 5:00:00 PM
Pre-Landfall 58/26/2012 10:20:00 AM  
Pre-Landfall 48/25/2012 10:45:00 AM  
Pre-Landfall 38/24/2012 2:20:00 PM  
Pre-Landfall 28/23/2012 3:00:00 PM  
Pre-Landfall 18/22/2012 3:20:00 PM  
Posting Date: 8/30/2012 11:30:00 PM
AIR estimates an expected (mean) insured industry loss to onshore U.S. property exposures from Hurricane (now Tropical Depression) Isaac of nearly USD 1.2 billion, with a 90% confidence interval of USD 700 million to USD 2 billion.
  • High Loss Scenarios: The high end of the range reflects higher storm surge depths, a slightly more intense storm and a larger radius of maximum winds.
  • Low Loss Scenarios: The low end of the range reflects lower storm surge depths, a less intense storm and a smaller radius of winds.
  • Sources of Significant Uncertainty: There remains significant uncertainty in the actual surface-level winds. Although the National Hurricane Center reported 80 mph winds at first landfall and second landfall in Louisiana, and maintained Isaac at hurricane status (winds > 74 mph) through 1:00 p.m. yesterday, August 29, these estimates are not reflected in actual measurements from onshore stations, which have been significantly lower in most cases. Further uncertainty results from the amount of rainfall that Isaac has produced and may continue to produce in its unexpectedly slow progress across Louisiana. Given the heavily saturated soils, trees will be downed by much lower wind speeds than would normally be required. Another question is the extent of leakage of flood damage into wind damage claims.

AIR estimates include wind and storm surge damage to onshore residential, commercial and industrial properties and their contents, automobiles, and time element coverage (additional living expenses for residential properties and business interruption for commercial properties).

Current and Forecast Conditions

As of the 4:00 p.m. CDT, August 30, Advisory from the National Hurricane Center, Isaac has at last been downgraded to a tropical depression. The center of the storm is located about 35 miles west-northwest of Monroe, Louisiana and is moving to the north-northwest at 12 mph. Maximum sustained winds have fallen to 35 mph.

All coastal warnings have been discontinued. However, inland flooding from continuing precipitation remains a risk and isolated tornadoes may still be spawned by the storm. Total rainfall accumulations of 7 to 14 inches are expected, with isolated amounts up to 25 inches.

Tropical Depression Isaac will turn to the north late tonight or early tomorrow, be over Arkansas tomorrow, and then southern Missouri by Friday night. Heavy rainfall will spread into portions of the Midwest and Ohio Valley this weekend.

Reported Impacts

Damage reports have mostly been focused on the flooding caused by Isaac's precipitation shield and slow movement. Nearly eight inches of rain were reported at the New Orleans International Airport yesterday. Much of the worst flooding occurred in Plaquemines Parish, Louisiana, where a combination of storm surge and rainfall caused water to top the earthen levees. Up to 12 feet of standing water was reported in parts of Plaquemines Parish yesterday, where as many as 800 homes are reported to have sustained significant water damage.

Within the last several hours, officials have reported that a dam near the border between Louisiana and Mississippi has a 50-50 chance of breaking. As many as 60,000 people have been ordered to evacuate the area. A controlled release of water from behind the dam has begun in the hopes of avoiding a failure.

Wind damage has been less extensively reported. However, Isaac’s slow forward speed and refusal to dissipate will exacerbate wind damage. As the winds persist, roof fasteners and connections can become fatigued and overloaded causing additional damage, and the possibility of damage from flying building debris persists. It should also be noted that with soils heavily saturated by rain, trees can be downed by much lower wind speeds than would otherwise be necessary.

Downed power lines, trees and other infrastructure are being reported over much of southern Louisiana and Mississippi. Some structural damage is being reported in New Orleans and the surrounding area, mostly limited to roof damage and to non-structural elements such as awnings, signage, and trailers. A few house collapses have been reported in New Orleans, specifically in the 7th Ward and Mid-City. In Kenner, Louisiana, the Pontchartrain Center has sustained roof damage. Isolated tornadoes have been reported, with at least one house being destroyed in Pascagoula, Mississippi. Other damage due to tornadoes has been reported in Gulfport, Mississippi. All flights out of the New Orleans International Airport have been canceled for today. It is estimated that more than 700,000 customers remain without electricity across five states, although efforts have now begun to restore power.

Offshore Impacts

Although Isaac has battered properties on the U.S. Gulf Coast for more than 36 hours, government officials have not reported any discernible damage to offshore oil and gas platforms. Shell plans to begin flyover inspections of its platforms sometime today, but many companies will likely not send out inspection teams until tomorrow. Production on many could restart as early as tomorrow.

According to the Bureau of Safety and Environmental Enforcement (BSEE), as of 11:30 AM August 29, approximately 95% of the current daily oil production and nearly 70% of the daily gas production in the Gulf of Mexico had been shut in. Some 505 platforms (about 85% of the total in the Gulf) and 50 rigs (about 66% of the total) had been evacuated. Rigs are mobile and can move out of harm's way, while platforms are situated permanently in one location. There have been no reports of platforms having lost their moorings and gone adrift.

AIR does not expect significant physical damage to rigs and platforms either from wind or waves. Furthermore, as a result of the Gulf hurricanes of 2005 (Katrina, Rita and Wilma), Hurricane Gustav in 2008, and the Deepwater Horizon disaster of 2010, business interruption is a much rarer coverage than in years past. Therefore, AIR does not expect significant insured losses to offshore assets in the Gulf of Mexico as a result of Isaac.

AIR Loss Estimates

AIR estimates an expected (mean) insured industry loss to onshore U.S. property exposures from Tropical Storm Isaac of near USD 1.2 billion, with a 90% confidence interval of USD 700 million to USD 2 billion.

AIR’s loss estimates reflect:

  • Insured physical damage to property (residential, commercial, industrial, auto), both structures and their contents;
  • Additional living expenses (ALE) for residential claims;
  • For residential lines, estimates reflect AIR’s view that insurers will ultimately pay 10% of modeled storm surge damage as wind losses;
  • For commercial lines, insured physical damage to structures and contents, and business interruption directly caused by storm surge, assuming a 10% take-up rate for commercial flood policies (Note: Other flood losses are not modeled or reflected in estimates); business interruption losses include direct and indirect losses for insured risks that experience physical loss;
  • For the automobile line, estimates reflect AIR’s view that insurers will pay 100% of storm surge damage;
  • Demand surge.

Loss estimates do not reflect:

  • Losses from scenarios in which the cyclone makes landfall at tropical storm strength;
  • Losses resulting from the compromise of existing defenses (e.g., levees);
  • Losses to uninsured properties;
  • Losses to infrastructure;
  • Losses from extra-contractual obligations;
  • Losses from hazardous waste cleanup, vandalism or civil commotion whether directly or indirectly caused by the event;
  • Other non-modeled losses;
  • Losses for U.S. offshore assets and non-U.S. property (AIR estimates these losses separately).

Hurricane Isaac
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