Storm Surge/Tide — Lower Jefferson, Louisiana

2017-06-21 to 2017-06-23 · Lower Jefferson, Louisiana

Event narrative

The USGS gauge at the Barataria Waterway south of Lafitte rose to a maximum of 3.15 ft NAVD88 at 9:15 am CST on June 22. Tides were at least 1.5 feet above normal from 6/20 through 6/22 at this gauge. The National Ocean Service gauge at Grand Isle reported a maximum water level of 1.94 ft MHHW, which was 1.8 ft above normal. The storm surge resulted in moderate impacts to the southern portions of the parish which are outside of the federal levee system. In Grand Isle, 30 ft of shoreline was eroded by the storm surge and wave runup. Flooding in the Lafitte area was limited to roads and low lying property with an inundation depth of generally 1 to 2 feet.

Wider weather episode

Tropical Storm Cindy developed over the central Gulf of Mexico on June 20th and moved generally northwest for the next few days before making landfall in southwest Louisiana near the Louisiana and Texas state line.

Cindy was an asymmetric system as it moved through the central Gulf toward southwest Louisiana, resulting in minor to moderate impacts across southeast Louisiana. The storm resulted in heavy rainfall, minor storm surge flooding, and isolated damage due to strong winds.

The minimum sea level pressure of 1004.4 mb, along with the highest wind gust and highest sustained wind in southeast Louisiana were all measured by the New Orleans Lakefront Airport ASOS. The highest wind gust recorded was 43 knots, or 49 mph, and the the maximum sustained wind in southeast Louisiana was 38 knots, or 44 mph. Tropical storm force winds were primarily experienced in gusts as squalls moved through the area. The winds did cause isolated minor damage to trees, roofs, and power lines. The only two known injuries in southeast Louisiana resulted from a tree falling on a mobile home in Houma.

A storm tide of generally 4 to 6 feet occurred along the Gulf Coast of southeast Louisiana from St. Bernard Parish through Terrebonne Parish. The highest measured storm tide was 6.18 ft NAVD88 at a USGS gauge near Point a la Hache in Plaquemines Parish. The elevated tides resulted in minor to moderate flooding mainly of low lying land and roadways outside the federal levee system.

Around Lake Pontchartrain, storm tide was generally measured in the 2 to 4 ft range, with a maximum value of 4.29 ft NAVD88 at the USCOE gauge near Mandeville. Again, impacts were minor to moderate with flooding to low lying land and roadways outside of levees systems.

Many areas of southeast Louisiana received 3 to 5 inches of rain with a few measurements in excess of 6 inches. Maximum storm total rainfall was 6.52 inches measured at a CoCoRaHS station in St. Bernard. The rainfall resulted in some minor river flooding across portions of the north shore of Lake Pontchartrain.

Source: NOAA Storm Events Database, event_id 715142. Narrative written by the NWS forecast office that issued the report.