It was the worst-case scenario many had predicted but which the people of New Orleans had prayed would never happen. Tens of thousands are trapped in the city surrounded by a hellish swamp of rising water that has washed away escape routes and swallowed up streets. There is no electricity or running water, telephone lines are down and the mobile phone system has crashed. Outside my hotel in central New Orleans, which is packed with 500 refugees from Hurricane Katrina, there is a knee-high soup of brown water swirling with debris from the storm - lethal shards of glass, road signs, sheets of metal, tree branches and lamp posts. In the lobby there is a stretch of water and a crowd of people wishing they were somewhere else. Many are wading out of the front door trying to reach vehicles to take the only route remaining out of the city after the twin-span causeway that leads across Lake Pontchartrain to the north was swept away. Many are carrying pillows and blankets on their heads and their possessions on their backs. One man mustered friends and family to carry his 100-year-old grandmother down five flights of stairs and onto a truck to get her out of the city. Some of those left behind have only the clothes on their backs, having fled to the hotel just before Katrina struck early on Monday. Some have no food and many are relying on the hotel's dwindling handouts of bottled water. Many have children, some even brought dogs and a number are infirm, disabled and unable to leave. There is misery, fear, desperation - and for those who could have evacuated sooner but didn't, regret. 'I wish I had evacuated when I could,' Anthony Peterson, 27, said. 'I wish I had listened. Now we're trapped like rats. I went to bed on Monday night with the streets dry and I woke up this morning to find I'm in Water World. The toilet isn't working, my mobile phone doesn't work and we only have a few cans of food that we are trying to stretch between four of us.' Worse still, Mr Peterson's home, close to Lake Ponchartrain, is almost certainly under water, possibly by as much as 4 metres. The only possessions he and his family brought with them to the hotel on Monday were some food, a few clothes and insurance papers. 'We might have to start our lives all over again when we get out if this,' Mr Peterson lamented. 'My only consolation is that I work as a roofer, so I'll have plenty of customers.' After Katrina roared through, areas to the east of the city have flooded but the central city district, historic French Quarter and other swathes of the metropolitan area seemed to have been spared the flooding. As I looked out the window of my room on the fifth floor at 6.30am, I found the scene was vastly different. Police Swat teams who had made their makeshift headquarters in the building opposite, were wading along the street with their trousers rolled up and their weapons held above their heads to keep them dry. People in the hotel are sitting in corridors and in their rooms huddled around radios trying to glean information. The devastation is worse than imagined. Governor Kathleen Blanco tells her people in a breaking voice to 'pray for patience, pray for courage'. Water is cascading over the top of the levees designed to protect the city from the lake and the Mississippi River. Beyond the levees, barges and boats are washed onto the river banks. While pumping stations are up and running, attempting to shift the water away from the city, that water is simply going back into the lake and river, which clearly cannot cope. People listen to the radio in horror as Jefferson parish president Aaron Broussard says the situation is 'critical'. In his parish, or county, to the east, 200 people were rescued overnight from rooftops by coastguard and police helicopters that clattered insistently over the city all night. In the Superdome, the football arena a few streets away that's now a makeshift refugee camp for as many as 30,000 people, residents were hot and restless. Some of the 4,000 National Guard troops who are patrolling the city and assisting the evacuation surrounded the Dome to form a security cordon as officials pleaded with the public to stay put. The hotel is in a low-lying spot in the bowl that forms the city of New Orleans. We are being told that the floodwaters we are seeing are coming from the breached canal levees to our north. Some people have taken to occupying sun-lounges beside the small rooftop pool. The water is black with filth from the storm and unfit for anything other than flushing toilets. They are not sunbathing, even though the sun is shining. They are contemplating how long they might be here. The hotel's back-up generator, which had enough diesel fuel for 30 hours, is now running low and the manager has announced he is switching off the emergency lighting to save the last of the fuel for nightfall so we at least have lights in the corridors. People are trudging up and down the emergency stairwells, several hobbling with walking sticks. All people can do is sit tight and try to ride it out, then try find a route west out of the city. There are still areas of high ground in the city, but lack of electricity, dwindling supplies of food, rising flood water and uncertainty make staying an impractical and unappealing option. People who have vehicles are scrambling to reach them, knowing that New Orleans is no longer the same place they called home.