The Bay of Fundy has always boasted the highest tides in the world, but on Tuesday tides will hit a peak that has not been reached in nearly two decades.

Francis LeBlanc, the dean of the faculty of social science at the University of Moncton, says the higher-than-usual high tide will reach 14.2 metres thanks to the supermoon this week. The supermoon, he explains, is when the moon, Earth and sun are more or less aligned.

"We had a supermoon on Sunday … the moon was close to its closest point from the Earth and the closer it is the more gravitational attraction there is. so we'll have higher tides," he said during an interview on Information Morning Moncton on Tuesday.

"In the Bay of Fundy, the tides are going to be 14.2 metres high, which is enormous."

He says high tides vary and Tuesday's tide will be approximately three metres higher than the lowest high tide, but only about five centimetres higher than the highest high tide. 

"Even though we have very high tides it's not particularly dangerous — it's only a couple of inches higher than it would normally be — let's say four or five inches higher than a very high tide would be," he said.

'In the Bay of Fundy, the tides are going to be 14.2 meters high, which is enormous.' -Francis LeBlanc, University of Moncton

A rainfall warning has been issued by Environment Canada with heavy rain expected to move in late on Tuesday, but LeBlanc says that shouldn't have any impact on the tides.

"But if we have a storm, then we can have problems," he said.

"The low pressure can pull in the water towards the land and cause flooding but this time we're not planning to have a storm, [we'll have] rain, but we shouldn't have flooding."

The most famous example of a storm coinciding with a high tide came in 1869, when the so-called "Saxby Gale" hit the region in early October, also at the height of the same 18-year cycle that peaks this week.

A two-metre storm surge pushed water levels above what was then the record for Moncton.