4. HIGH TIDES COULD WORSEN FLOODING
Further complicating matters is the possibility for dangerous storm surges: A full moon means the tides will be higher than usual, which will make it easier for the storm's powerful winds to push water into low-lying areas. That, coupled with the threat of several inches of rain, has officials working to shore up flood defenses.
Storm surge could reach anywhere from 2 to 11 feet along the northeastern coast, forecasters say. Inland river flooding also is a serious concern.
5. COMBO OF SNOW, WIND INCREASES RISK FOR WIDESPREAD POWER OUTAGES
Storms in recent years have left hundreds of thousands of people in the eastern U.S. without power, sometimes for days at a time. Utilities have been bringing in extra crews and lining up tree trimmers so they're prepared, and with good reason. The superstorm brings two possibilities for knocking out electricity. For one, hurricane-force winds of at 74 mph could send tree branches into power lines, or even topple entire trees and power poles. Those left standing could succumb to snow, which could weigh down still-leafy branches enough to also topple trees.