Hurricane Isaac: New Orleans braces for test of its storm preparations (+video)
With maximum winds from Hurricane Isaac expected to be 80 miles an hour, the storm's main threat is posed by water. The new New Orleans surge barrier has been closed for the first time.
Tropical storm Isaac reached hurricane status early Tuesday afternoon as it bore down on a shuttered southeastern Louisiana.Skip to next paragraph
Subscribe Today to the Monitor
And while the storm is expected to make landfall Thursday night with maximum sustained winds of about 80 miles an hour, the storm's biggest threat is posed by water – from the storm surge initially, along the coast, and flooding inland.
For the first time since it was built following hurricane Katrina in 2005, a $1.1-billion surge barrier has been closed to help protect New Orleans from surge-related flooding. The barrier, some 26 feet high and 1.8 miles long, is designed to prevent a storm surge from rolling up a shipping canal the US Army Corps of Engineers built at the behest of Congress to cut the amount of time it takes for ships to travel between New Orleans and the Gulf.
IN PICTURES: Hurricane Isaac
In addition, following Katrina, the Corps of Engineers was given the job of repairing and upgrading the system of pumps that draw storm water out of New Orleans, just under half of which is below sea level. New Orleans Mayor Mitch Landrieu pronounced all of them ready for operation during Isaac's downpours.
Several parishes have ordered mandatory evacuations for communities on the coast. Isaac's category 1 rating, however, is too low to trigger mandatory evacuations for New Orleans. Even so, at a press briefing Tuesday, Mayor Landrieu strongly encouraged people who live in Orleans Parish outside the city's levee system to evacuate.
Meanwhile, in Washington, President Obama declared states of emergency for Louisiana and Mississippi, setting the stage for the Federal Emergency Management Agency to coordinate relief efforts and provide other forms of assistance to stricken areas.