Why is Super Typhoon Bavi, nearing US Pacific Islands, described as 'very dangerous'?

Super Typhoon Bavi is heading towards US Pacific territories of Guam and Northern Mariana Islands with maximum sustained winds of up to 280 kmph. US National Weather Service has described Bavi as "very dangerous" storm. It warned that areas near its eye could experience catastrophic wind damage, dangerous storm surges and hazardous surf as it moves westward across the region.