A National Weather Service Survey Team said Wednesday that damage near Arabi in St. Bernard Parish was consistent with at least an EF-3 tornado, which has maximum winds of between 136 to 165 miles per hour.
The tornado is blamed for one death and numerous injuries as it barreled across the Westbank near Gretna before moving over the river towards the Lower 9th Ward and Arabi.
The team added a final assessment is expected to be complete in the next day or two.
Another survey team reached a preliminary assessment that the tornado that struck the Northshore Tuesday night was at EF-1 strength, with maximum winds of 90 miles per hour.
The NWS said the tornado started near the Big Branch Marsh National Wildlife Refuge on Highway 190 just before 7:30 p.m.
"Damage began at homes just north of 190, including minor roof damage, a shed destroyed, and dozens of trees snapped," said the team.
The twister then continued northeast, crossing Interstate 12 and tracking along Highway 1088 to just southwest of Highway 36, where dozens of trees were downed, before continuing another three miles north of Highway 36 in mainly rural areas.
In all, the tornado traveled just over 12 miles in about eight minutes before weakening.