Hurricane Isaias

Post Landfall 1 | Summary
Posting Date: August 7, 2020, 5:00:00 AM

As Isaias made its way up the U.S. East Coast as a tropical storm starting in the early hours of August 2, it impacted Florida, Georgia, and South Carolina with winds of up to 40 mph and heavy rains. Hurricane Isaias made landfall near Ocean Isle Beach, North Carolina, as a Category 1 storm with wind speeds of 85 mph around 11 p.m. on August 3. Wilmington, North Carolina, saw wind gusts up to 74 mph. Storm surge over 4 feet above normal tide level and riverine flooding were reported in some areas relatively close to landfall. It is noteworthy that Isaias was upgraded to a Category 1 hurricane just prior to landfall in North Carolina.

A few hours after landfall as Isaias moved relatively quickly over land early on August 4, it weakened to a tropical storm. Isaias brought tropical storm–strength winds, hurricane-force gusts and heavy rains along its path through not only North Carolina but also through Virginia, Washington, D.C., Maryland, Delaware, and Pennsylvania. The storm downed trees and caused power outages in the region. The storm also spawned dozens of tornadoes and caused localized flooding. Notable rainfall included 7 inches reported in parts of southern Maryland and 3 inches in Washington, D.C., along Interstate-95 and at Reagan National Airport.

Isaias maintained tropical storm strength nearly all through August 4. By late morning that day, it was roughly 70 miles southwest of Philadelphia. The storm continued to move relatively quickly northeast through New Jersey, whose shore was impacted by high winds, frequent gusts of 60 to 70 mph, and heavy rainfall; a state of emergency was declared at 5 a.m. on August 4 and all state offices were closed. Isaias also impacted New York City and Long Island, which experienced sustained winds of up to 65 mph and frequent gusts of 60 to 70 mph, with a gust of 78 mph recorded in the Battery Park neighborhood of the city. New York’s JFK and LaGuardia airports each canceled dozens of flights. Both New Jersey and New York had many trees toppled by the storm, which brought down power lines and caused more than 1 million customers there to lose power.

Isaias brought wind gusts of more than 50 mph, heavy rains, and localized flooding to New England states. The storm toppled many trees in this region as well, which brought down power lines and cut power to more than 1 million customers in the Northeast—notably 700,000 in Connecticut and 200,000 in Massachusetts. Just before midnight on August 4, Isaias was classified as post-tropical, and headed north to eastern Canada.

AIR's internal analysis of the storm and its impacts show that the losses in Mid-Atlantic and Northeastern states could equal and even exceed those from the Carolinas, Georgia, and Florida. Losses could further accumulate from such localized impacts as tornadoes and flash flooding. Treefall in the Northeast states not only resulted in downed power lines and outages but also damage to homes; the uprooting of trees could have been exacerbated by the ground’s saturation from rainfall prior to Isaias’ impact.

Post Landfall 1 | Downloads
Posting Date: August 7, 2020, 5:00:00 AM