In New Zealand, strong winds whipped up huge dust clouds in the earthquake-hit Christchurch today, hampering the search for bodies. Gusts of 70 kilometres per hour buffeted emergency teams in the ruins of the second largest city, amid fears of masonry dislodging and trees toppling. District police commander Dave Cliff told reporters that the winds stirred an estimated 200,000 tonnes of silt and sand pushed up from the ground after the power of the February 22 quake loosened the bond between soil particles in a process called liquefaction.Meanwhile, the death toll from last week's 6.3-magnitude tremor stood at 159 today, climbing toward a final tally that police expect to exceed 240. Rescuers have conceded they do not expect to find any more survivors, turning attention to questions about why the damage inflicted on the city in the 6.3-magnitude tremor was so severe. Up to a third of the city centre's buildings face demolition after the quake left them cracked and teetering, while two office blocks concertinaed and were completely destroyed.