Storm surge and rough seas produced by the hurricane along the Louisiana coast arrived shortly before the storm made landfall. Evacuees departing the coast as late as September 28 reported no abnormal tides along the shore. However, sea levels began to rise at abnormally rapid rates on the morning of September 29 as the hurricane neared. By the afternoon hours, low-lying lands south of New Orleans and east towards Bay St. Louis, Mississippi, as well as areas adjacent to Lake Pontchartrain, were inundated by the quickly rising storm surge. Levee overtopping along Lake Pontchartrain resulted in the flooding of much of western New Orleans. Parts of Carrollton, New Orleans were submerged under as much as 8 ft (2.4 m) of water due to the levee failure, and much of this inundation remained for up to four days as the city's drainage system slowly drained the floodwaters; in other locations, floodwaters receded rapidly. At its height, the surge was estimated to have crested between 15 and 20 ft (4.6–6.1 m) in height, setting a record for the highest tide reported in the region. Ocean swells topped levees along the Mississippi River and progressed well upstream; at the confluence of the Harvey Canal and the Mississippi River nearly 100 mi (160 km) from the Gulf of Mexico, the river swelled to 6 ft (1.8 m) above normal. Elsewhere, waves 10–12 ft (3.0–3.7 m) above normal high tide were reported along the same river.