Tacloban, 201 square kilometres in area, had 221,000 residents. Metropolitan Manila, a sprawling patchwork of 16 cities and one municipality, has up to 15 million people living in 638 square kilometres.

According to Dr Mahar Lagmay, director of Project NOAH (Nationwide Operational Assessment of Hazards), a visit by a Haiyan-class typhoon is a "possibility". He added: "It's Russian roulette."

Through its 442-year history, the metropolis has been battered by typhoons, destroyed several times by earthquakes and flooded regularly. Typhoons are part of life in Manila. Typically, a powerful storm brings floods, strong winds and power blackouts. Although Metro Manila has yet to suffer a category 5 storm like Haiyan, it's already had deadly warnings of what might happen.

In 2009, intense rains brought by Typhoon Ketsana submerged the metropolis, killing at least 250 people. The deluge was unprecedented: in low-lying areas, water was deep enough to submerge two-storey houses. Streets became raging torrents that drowned the unwary and swept vehicles away like toys. Large parts of the city were cut off and many residents spent days huddled on their rooftops.

In 2011, Typhoon Nesat introduced Manila to unprecedented storm surges. Large waves from Manila Bay wrecked lengths of the seawall and brought waist-deep floods to nearby areas. Last year, Typhoon Saola caused yet another surge that again knocked down the seawall and deposited tonnes of rubbish and filth along the seaside Roxas Boulevard.

The metropolis lies sandwiched between the vast Manila Bay to the west and Laguna de Bay to the east. Water drains from Laguna de Bay, which is higher in elevation, to the sea through only one river, the Pasig, and if that is blocked the city floods.

If a storm surge of the type that destroyed Tacloban came in from Manila Bay, the lake would have no place to drain and there could be successive high wind-driven waves.

Project NOAH's Lagmay said the 2011 storm surge was 1.5 metres high, "with splash waves higher than the coconut trees". By comparison, Haiyan's surge was five metres.

Dr Fernando Siringan, a marine and coastal geologist, said a devastating surge through Manila would require a typhoon with Haiyan's wind velocity, oriented southwest of Manila Bay. A surge during high tide would add one metre to the wave's height.

"Low-lying areas directly facing the city would be worst hit - Manila proper, Malabon, Navotas and all the towns in the bay head."

Even structures far from the surge would be damaged by a super storm's winds. Dave Lorito, a communications officer for an international bank, asked his architect what would happen to his house, which is well inland from the bay.

"All glass windows shattered, 50 per cent of the roof blown off and the second floor ceiling totally damaged," he was told.

Jonathan Ravelas, chief market strategist of BDO Unibank, said a Haiyan-class storm "could really paralyse the capital and affect the country's GDP growth". He noted that "because of Typhoon Ondoy [Ketsana], our GDP growth dropped from 1.6 per cent in the second quarter to 0.5 per cent in the third."

Asked if the government is prepared for a Haiyan-type storm in Manila, Project NOAH's Lagmay replied: "No comment."