Hurricane Ike is the most powerful hurricane so far this year. On Saturday it destroyed most of the buildings on the Turks & Caicos Islands as a Category 4 hurricane, reaching wind speeds of 225 km/h (140 mph). It then tore through Cuba and dropped more rain on Haiti, already ravaged by floods from Tropical Storm Hanna last Thursday.

But Ike did not behave according to plan. It seemed to be following in the wake of Hanna as it skirted the outer fringes of the West Indies, apparently preparing for an attack on the East Coast of the US. But forecasters watched in amazement when Ike suddenly turned left towards Cuba, missed Florida and headed deep into the Gulf of Mexico — a very unusual track for a hurricane in mid-September.

It is a treacherous path to take. As the storm swept the length of Cuba it had weakened considerably, but it is now reinvigorating itself in the Gulf’s warm waters, a rich fuel supply that is feeding the storm’s voracious appetite for energy. It was thought that New Orleans would again be in the line of fire, so soon after the mass evacuation for Hurricane Gustav. But Ike now seems to be heading for a strike on Texas, where a million people are preparing to evacuate their homes.

So what made Hurricane Ike take such an unusual track? It was pushed off course by a huge block of high pressure over the southeast corner of the US. Rather like the way a boulder in a river makes water flow around it, so a hurricane is steered around a high-pressure system. Despite their awesome power and size, hurricanes are simply no match for a hefty anti-cyclone.