Mississippi and Atchafalaya River Flood Briefing May 9, 2011 National Weather Service Lower Mississippi River Forecast Center and Weather Forecast Office New Orleans/Baton Rouge and Jackson, MS National Weather Service Lower Mississippi River Forecast Center and Weather Forecast Office New Orleans/Baton Rouge and Jackson, MS

Rainfall Next 5 Days Pattern Brings Light to Moderate Rain to Ohio and Mississippi River Basins

Extended Forecast May 11May 12May 13 May 14May 15

LocationLevee Height at gage Current Forecast Crest without Morganza Contingency Forecast Crest with Morganza Vicksburg 112.5* Natchez 84.3* Red River Landing 68.3* – 64.5 Baton Rouge 51.4* – 46.5 Donaldsonville 36.6* Reserve 32.7* New Orleans 24.0* Mississippi River Crests With and Without Morganza Operation * Levee Heights provided by U.S. Army Corps of Engineers

LocationLevee Height at Gage Current Forecast Crest without Morganza Contingency Forecast Crest with Morganza Simmesport62.0* 50.0 Melville WARL 53.0* EARL 48.5* 40.0 Krotz Springs WARL 45.12* EARL 41.5* 35.0 Butte LaRose WARL 25.5* Bayou Sorrell Proper Myette Point WABPL Morgan City21.7* – 13.0 Atchafalaya River Crests With and Without Morganza Operation * Levee Heights provided by U.S. Army Corps of Engineers

Mississippi River Forecast Crest Height at 57.5’ May 19th Crest Height at 64.0’ May 21 st Crest Height at 65.5’ May 22nd Crest Height at 47.5’ May 22nd Crest Height at 36.0’ May 22nd Crest Height at 28.0’ May 23 rd Crest Height at 19.5’ May 23rd Assumes NO Morganza Operation

Mississippi River Forecast Crest Height at 57’ May 20th Crest Height at 62.5’ May 22rd Crest Height at 63.5’ to 64.5’ May 23rd Crest Height at 45.5’ to 46.5’ May 23rd Crest Height at 35.0’ May 23rd Crest Height at 25.0’ May 24 th Crest Height at 17.0’ May 24th Assumes Morganza Operation

Atchafalaya River Basin Crest Height at 9.5’ May 25 th Assumes No Morganza Operation Crest Height at 50.0’ May 23 rd Crest Height at 40.0’ May 23 rd Crest Height at 35.0’ May 24 th Crest Height at 25.0’ May 24 th Crest Height at 14.0’ May 25 th Crest Height at 14.5’ May 25 th

Atchafalaya River Basin Crest Height at 12-13’ May 25 th Assumes Morganza Operation Crest Height at 50.0’ May 23 rd Crest Height at 40.0’ May 23 rd Crest Height at 35.0’ May 24 th Crest Height at 27.0’ May 24 th Crest Height at 21.5’ May 25 th Crest Height at 19.0’ May 25 th

DATECREST  05/28/ RECORD  06/27/  04/05/  04/18/  06/06/ MORGAN CITY IMPACTS FORECAST CREST (NO Morganza)– 9.5 FT FORECAST CREST (Morganza) – 12 to 13 FT

 4 ft – Water will move up the bank and across access roads below the city dock. Vessel Traffic safety rules will be strictly enforced by the US Coast Guard. Minor  5 ft – Floodwall gates will be closed to protect against higher stages. Vessel traffic will be affected by stronger river current and vessel traffic safety rules will be strictly enforced by the U. S. Coast guard. Minor  6 ft – The city dock will be under water. Water will cover the lower end of Belleview Front street in Berwick. Vessel traffic will be affected by stronger river current and vessel traffic safety rules will be strictly enforced by the U. S. Coast guard. Minor  7 ft – Buildings at the foot of Ann street on the river side of the flood wall will flood as water overtops the Rio Oil Company dock. Buildings on the river side of the Berwick floodwall will flood. River traffic restrictions will be strictly enforced. Moderate  9 ft – structures on the river side of protection walls in Morgan City and Berwick will be under water. River traffic restrictions will be strictly enforced. Moderate MORGAN CITY FORECAST CREST – 9.5 FT

 THERE IS A MAJOR FLOOD THREAT.  BACK WATER FLOODING OF 5 TO 6 FEET AT BAYOU BOUEF WILL CAUSE DAMAGE EAST OF MORGAN CITY TO THE COMMUNITY OF AMELIA.  STRUCTURES ON THE RIVER SIDE OF PROTECTION WALLS IN MORGAN CITY AND BERWICK WILL BE UNDER WATER. RIVER TRAFFIC RESTRICTIONS WILL BE STRICTLY ENFORCED. MORGAN CITY FORECAST CREST – FT

Records on Mississippi River Red River Landing 1)62.30 ft on 03/25/1997 2)60.94 ft on 05/14/1927 3)60.96 ft on 04/25/2008 Current forecast crest 65.5 ft Baton Rouge 1)47.28 ft on 05/15/1927 2)45.18 ft on 05/16/1922 3)45.18 ft on 04/29/1945 Current forecast crest 47.5 ft Donaldsonville 1)36.01 ft on 05/15/1927 2)34.75 ft on 05/16/1922 3)34.11 ft on 04/29/1945 Current forecast crest 36.0 ft 1)36.01 ft on 05/15/1927 2)34.75 ft on 05/16/1922 3)34.11 ft on 04/29/1945 Current forecast crest 36.0 ft Reserve 1)26.00 ft on 06/11/1929 2)25.90 ft on 04/28/1945 3)25.60 ft on 03/05/1932 Current forecast crest 28.0 ft 1)26.00 ft on 06/11/1929 2)25.90 ft on 04/28/1945 3)25.60 ft on 03/05/1932 Current forecast crest 28.0 ft New Orleans 1)21.27 ft on 04/25/1922 2)21.02 ft on 05/11/1912 3)21.00 ft on 04/25/1927 Current forecast crest 19.5 ft 1)21.27 ft on 04/25/1922 2)21.02 ft on 05/11/1912 3)21.00 ft on 04/25/1927 Current forecast crest 19.5 ft