Storm Surge/Tide — Harrison, Mississippi

2012-08-28 to 2012-08-30 · Harrison, Mississippi

Wider weather episode

Hurricane Isaac entered the Gulf of Mexico as a tropical storm on August 26, moving northwest after crossing Haiti, Cuba and the Florida Straits. Isaac moved slowly north northwest over the eastern Gulf . Isaac strengthened into a hurricane on the morning of the 28th when it was 75 miles south southeast of the mouth of the Mississippi River. Isaac made landfall in Plaquemines Parish as a Category 1 Hurricane near Southwest Pass of the Mississippi River on the evening of the 28th. A second landfall occurred near Port Fourchon the following morning. The storm weakened to a tropical storm on the afternoon of the 29th about 50 miles west southwest of New Orleans, and weakened further to a tropical depression on the afternoon of the 30th near Monroe, Louisiana.

Even though Issac was of hurricane status from near the mouth of the Mississippi River into southeast Louisiana, only tropical storm force winds were recorded on land areas of Mississippi. The maximum sustained wind in south Mississippi was 46 knots or 53 mph measured at the Gulfport Airport (KGPT) during the early afternoon of August 29th. A portable weather station (Weatherflow Inc) near Gulfport measured a 48 knot gust, or 55 mph, late on the morning of August 29. Maximum wind gust of 58 knots or 67 mph was recorded at the NOAA NOS Bay Waveland station and also at Gulfport (Weatherflow Inc) late on the morning of Aug 29. The long duration of tropical storm force winds downed some trees and power lines across the region.

The minimum sea level pressure measured from a land station was 995.9 mb the NOAA-NOS station at Bay-Waveland station during the early morning of Aug 29th.

A storm tide ranged from approximately 5 feet in Jackson County to nearly 10 feet in Hancock County closer to Isaacs's center. These values are approximately 3 to 8 feet above normal astronomical values. Storm surge flooding impacts were greatest in Hancock County.

Persistent rainbands affected south Mississippi, especially the coastal sections produced heavy rainfall over a three day period. 10 to 20 inches of rainfall was common across the region. A co-operative observer near Pascagaoula recorded the maximum reading of 22.20 inches of rain. Heavy rainfall produced both flash flooding and later moderate to major river flooding. Record crests were observed on the Wolf River near Landon (Aug 31) and Gulfport (Sep 1), and the East Hobolochitto River near Cesear (Aug 31). Storm surge and high tides restricted outflow of the rivers near the coast and lakes exacerbating flooding of low lying areas along rivers and bayous near the coast as they emptied into the Gulf.

There were two weak tornadoes documented that occurred along Mississippi coast which resulted in generally minor property damage.

Overall , impacts from Isaac resulted in at least $7 million in damages in south Mississippi and one direct fatality. Much of the damage in the coastal counties of Hancock, Harrison, and Jackson, damage was related to storm surge on the coast, flash flooding, or river flooding. There will likely be adjustments in the damages as additional information and assessments are made. There was one direct fatality in south Mississippi on morning of Aug 30 when a tree fell on a tow truck killing the 52 year old male driver.

Source: NOAA Storm Events Database, event_id 410176. Narrative written by the NWS forecast office that issued the report.