A full moon occurring this afternoon will make tides higher than normal along North America's East Coast, leading to stronger potential storm surges and even more possible damage from Hurricane Sandy as it hits land.

The moon reaches its full phase at about 3:50 p.m. ET on Monday, meaning that the gravitational force affecting tides will be at its greatest. The storm surge is expected to occur with high tides this evening.

"The largest immediate threat to life will be with storm surge of one to three metres in height occurring with higher-than-normal tides as we are close to a full moon," CBC meteorologist Jay Scotland said Monday.

New York Gov. Andrew Cuomo warned of storm surges even higher than those that occurred during Hurricane Irene in 2011.

"We're talking about surges that we have not seen before," Cuomo said, urging anyone left in Lower Manhattan to leave the area immediately.

"With the moon in its full phase, high tides on Earth will rise about 20 per cent higher than normal." NASA spokesman Rob Gutro wrote Sunday.

"The full moon will add more power to the already intense storm surge of Hurricane Sandy, which is already expected to reach heights of six to 11 feet (1.8 to 3.3 metres) in parts of Long Island Sound and New York Harbor."

Next high tides

High tides along the Atlantic coast occur about twice a day, with the next one forecast by windfinder.com for 9:06 p.m. ET in New York City.

The next high tides for Port Lorne, N.S., on the Bay of Fundy — an area known for the world's highest tides — occur at 12:23 p.m. AT Monday and again shortly after midnight, at 12:48 a.m. AT Tuesday.

While the moon may be full, it's not at, or even near, its "perigee," or point closest to Earth. That would have made matters even worse for coastal communities, according to U.S. meteorologist Joe Rao, who was cited by CBS News.

In New York Monday, Metropolitan Transit Authority chairman Joseph Lhota also cautioned that electronic switches and wiring in the city's subway system would be much more severely damaged by incoming sea water than by conventional rainwater or flooding.

"Our subway system and salt water do not mix very well together," he told a joint media conference with Cuomo and other authorities.