Saturday night's Krewe du Vieux parade was an absolute delight - there's no way you'd guess that post-Katrina New Orleans is a city on its knees, abandoned by half its population.

Sixteen sub-krewes (Pam's is the Krewe du Craps), each with its own float, marched through the packed streets of the French Quarter to a cacophony of battered old trombones and euphoniums. Every time the congestion brought us to a halt, an impromptu street party sprang into existence, stranger conversing with stranger.

I don't think I've ever seen such a huge outpouring of warmth, enthusiasm and friendliness on such a chilly night. I especially enjoyed the throws - in a time-honoured carnival tradition, the paraders hurl armfuls of cheap trinkets into the crowd. In our case it was strings of beads, and as well as throwing them we placed them round the necks of anyone who took our fancy, extracting a kiss and a 'Happy Mardi Gras' in return.

The overall theme of the parade was Habitat for Insanity, a pun on the international housing charity Habitat for Humanity, which has played a major part in rehabilitating houses since the hurricane.

Mardi Gras is an excuse for New Orleanians to let their hair down, but it also has a serious satirical intent - this theme was a reminder that many people were badly traumatised by Katrina and there's been a significant rise in the incidence of mental health problems. Our float was a covered wagon bearing the words 'Home, home and deranged' and with a box on the side supposedly dispensing free Prozac - though the hundreds of people who opened the lid were in for a big disappointment: it was empty.

Thanks to a dead camera battery, I don't have a single photo. Never mind.

I'm going back soon for the climax of Mardi Gras, but in the meantime I have some serious walking to do. I crossed the New Mexico state line today, and I'm now in Hobbs, a city of some 30,000 that sprawls eastwards into Texas. It was a hot day, and I ended up doing something I hadn't done for many months: I drank my water supply dry and had to approach a stranger for more.

This is still oil country, and the air was thick with its tarry, cloying smell; the locals probably don't even notice, but I found it almost unpleasantly intense.

Despite the small-town decay I've seen all across Texas, high oil prices mean that the local economy is booming: everyone has a shiny new car, and even the most expensive restaurants are full. It won't last for ever, though, because the state's onshore reserves are running out.

Apart from thousands of oil wells, the other very obvious feature of the landscape is irrigation. Much of the watering is done by pivots, enormously long wheeled arms which either traverse the fields lengthwise or rotate on their axis, creating a perfect circle of brilliant green in a square of strawy brown semi-desert. This area must look beautiful from the air.