New Zealand braced for more destruction on Sunday as aftershocks and an approaching storm threatened an area of the country hit by the most devastating earthquake in decades. Prime Minister John Key said it was "a miracle" no one had died when the major 7.0 magnitude quake wreaked more than a billion dollars of damage on the nation's second-biggest city of Christchurch. Civil defence officials warned that ongoing aftershocks with magnitudes of up to 5.4,coupled with a ferocious storm blowing in could threaten already-weakened buildings. Despite widespread damage,none of the city's 340,000-strong population died when the quake struck before dawn Saturday. "The only conclusion you can draw is that it's a miracle nobody was killed," Key said as he surveyed the devastation. "Parts of the city look like they've been put in the tumble dryer and been given a darn good shake." Central Christchurch remained cordoned off today although most of the power,water and sewage facilities that were cut in the earthquake had been restored. Emergency evaluation teams picked their way through streets piled with rubble and littered with shattered glass to inspect buildings and determine whether evacuations were necessary. Some coastal and riverside suburbs "are the worst-hit areas in the city and public health issues may yet force evacuations," the civil defence agency said in a statement. More than 200 people spent Saturday night in welfare centres while hundreds more sheltered with friends after fleeing damaged homes.