What is the difference between a hurricane and a typhoon?

The name: in the Atlantic and the eastern Pacific Ocean, they are hurricanes. In the north-western Pacific Ocean they are known as typhoons.

How big is Haiyan (known locally as Yolanda)

Bigger than hurricane Camille, which hit the US in 1969, and Allen in 1980, with wind speeds of at least 190 mph. The storm is 500 miles wide, wider than Katrina at its peak.

Is it the biggest ever?

This we cannot say because recorded history is limited to humans' ability to measure and verify wind speed and pressure. But it is the largest recorded since Allen.

Is it a super-typhoon?

Yes. To be classified as a hurricane, typhoon, or cyclone, a storm must reach wind speeds of at least 74 mph. If a typhoon hits 150 mph then it becomes a super-typhoon.

What are the main dangers?

Ferocious windspeeds and rainfall, flooding, damage to buildings, infrastructure, landslides, power cuts, and resulting food shortages all provide imminent danger to 25 million people in its path.