Storm surge is biggest potential impact for St. Mary

Hurricane Delta is approaching its expected landfall in Cameron Parish, and the biggest likely impact in St. Mary continues to be the storm surge.

A National Weather Service livestream at 10:30 a.m. continues to put St. Mary in the zone expecting 7-11 feet of storm surge.

That seems likely to mean coastal flooding, particularly in low-lying areas of western St. Mary. Parish officials on Thursday called for a voluntary evacuation of St. Mary west of Calumet.

A mandatory evacuation has been ordered for areas south of the Intracoastal Waterway.

The St. Mary Parish Levee District has moved to prevent water from the Intracoastal from causing flooding in the Bayou Sale area. It has also arranged to have sheet piles placed across the opening in the Bayou Chene Flood Control Structure, where construction is still incomplete. The sheet piles cover the 70-foot opening where a gate would be in the completed structure.

The structure is designed to prevent storm surge from coming up the Charenton Canal and into Bayou Teche, flooding the Franklin-Garden City-Centerville area.

At 9 a.m., the Atchafalaya River at Morgan City was at 3.28 feet. The predicted crest has been lowered, and is now expected to reach 6.5 feet late Friday night. The moderate flood stage is 7 feet.

The NWS livestream put St. Mary in the zone expecting 1-1.5 inches of rain and winds of tropical storm strength, 38-74 mph. If recent history is a guide, that's enough to cause some power outages.

The risk of tornadoes is rated as slight.