Thousands of people are evacuating the fourth largest city in the US as Hurricane Rita approaches. Highways north out of Houston have been jammed with cars.With memories of Hurricane Katrina fresh in their minds, Texans are not taking any chances. The state governor has urged residents to leave this stretch of the Gulf Coast immediately. Time is running out – Houston’s two main commercial airports are due to be shut down at midday today. Rita is currently rated a category 4 storm, with winds of up to 225 kilometres an hour. The latest predictions are it will veer northwest towards the refining and chemicals centre of Beaumont. The resort island of Galveston is the site of America’s worst natural disaster – in 1900 eight thousand people died when a category 4 hurricane passed over. The city, which lies 2 and a half metres above sea level, has been boarded up, and left deserted. One of the country’s biggest nuclear reactors, which lies on the Gulf Coast, has been shut down. A few hardy surfers have been taking advantage of the storm swell. Authorities say those who have not left yet should now stay where they are.