First look on the bleak side. President Bush says New Orleans and the neighbouring Mississippi coast has been devastated more than New York was by the terrorist attacks of September 2001.
Seeing the fearsome aerial photos, one fears the human tragedy may be greater.
So may the economic consequences. New York's financial community got back to business almost as usual with an extraordinary display of human resilience - and astonishingly effective contingency planning. The financial markets were shaken, but far from shattered.
In the wake of Katrina, the issue is the oil industry. On Wednesday, 91 per cent of the Gulf's crude output was said to be shut, along with eight refineries - more than ten per cent of all America's capacity. There were reports of platforms drifting helplessly round the Gulf and ruptured pipelines blazing.
Worse, in a sense, Americans were paying $3 a gallon for petrol, a price that Stuart Thomson at Charles Stanley Sutherlands fears could be the tipping point for the global economy - a price that deters Americans from buying other things, including imports from China where the economy may already be slowing sharply on its own.
Well, it hasn't happened yet. The bleak view may under- rate the vigour Americans apply to sort things out after a disaster - I saw it in Florida last year after hurricane Ivan.
Last night one company with a Gulf refinery said the flooding had caused "no major damage", another that the damage to its plant was "minor" and a third that it should be back in production by Sunday.
That still leaves a shortage of petrol. But that can be shipped in from the rest of the world - at a cost.
Americans may well have less to spend on other things. But there is also multi-billion tide of insurance money heading for New Orleans. That will create a few jobs.
