Hurricane ISAAC - New Orleans, Louisiana - August 28-29, 2012

Описание: From August 28th - 29th, 2012 storm chasers Michael Laca, Robert Jones, Greg Nordstrom and Devin Toporek intercepted Hurricane Isaac in downtown New Orleans and the surrounding areas of southeastern Louisiana.

With the large windfield and slow motion of Hurricane Isaac, impacts in southeastern Louisiana began well before the closest point of approach to the hurricane's center. By 10am CDT on the morning of August 28th, tropical storm conditions had already begun near the mouth of the Mississippi river in extreme southeastern Louisiana and continued to spread farther inland throughout the day. By late evening, strong convection associated with the core of Isaac was rapidly approaching New Orleans and winds in the downtown area began to increase dramatically.Our chase team's position, in a highly urbanized location, experienced significantly stronger winds in several isolated areas compared to many surrounding sites, due to the accelerated wind flow around the large high-rise office buildings and hotels in the downtown New Orleans area.

Between 3:30 am and 5:00 am CDT (0830 and 1000 UTC), Hurricane Isaac's northern eyewall moved over downtown New Orleans and our chase team's location. The peak normalized (1-min 10m) surface winds we experienced during this time were likely sustained around 65 mph (55 kt) with gusts to 75-80 mph (65-70 kt). However, in isolated locations, especially along Poydras and Canal streets, where the wind flow was accelerated around and down some of the larger buildings, peak gusts likely approached 95-105 mph (85-90 kt), frequently coming in powerful downward bursts, or resulting in turbulent vortex shedding where winds would change direction 180 degrees in just a few seconds. With the intense rainfall that accompanied the storm's eyewall, Hurricane Isaac was a significantly different experience in downtown New Orleas than in many surrounding areas.

The minimum pressure observed by our team was 983.0 mb (29.03 in) at 6:42am CDT (1142 UTC) on August 29th. However, given the hurricane's slow movement, the barometric pressure remained near its minimum value all the way through 9:45 am CDT (1445 UTC), fluctuating between 983-984 mb (29.03 - 29.06 in) during that period.

Damage throughout the downtown area was characteristic of a category one hurricane, with trees snapped or uprooted, unprotected plate glass windows broken, business awnings and scaffolding torn loose, street lamps and traffic signals broken off and metal siding ripped from some buildings.