How did Hurricane Irma get to be a ‘monster’ storm and will it happen again?

Hurricane Irma has already wrought destruction on some island nations in the Caribbean, killing at least four people and levelling buildings, and it looks as though the category 5 hurricane is heading towards the eastern U.S. coast.

In all, the United Nations expects it to affect as many as 37 million people.

LIVE UPDATES: Tracking Hurricane Irma’s path

With winds of nearly 300 km/h, it’s the biggest storm in the Atlantic in over 35 years, with only Hurricane Allen in 1980 being faster (at 305 km/h).

U.S. National Weather Service Director Louis Uccellini says Hurricane Irma is so record-breaking strong it’s impossible to over-hype. Uccellini told The Associated Press on Wednesday he’s concerned about Florida up the east coast to North Carolina, starting with the Florida Keys.

Hurricane expert Kerry Emanuel of MIT calculates that Irma holds about seven trillion watts – about twice the energy of all bombs used in the Second World War.

Other meteorologists were at a loss of words.

Athena Masson, an environmental science PhD researcher from the University of Toronto with a specialty in Atlantic-based hurricanes, called the storm “a monster.”

So how exactly did it get to be this “monster” that we’re seeing now?

“It started out in the Cape Verde region,” Masson explained. “It formed so far out there in the tropical warm waters, and it has had all this time to cross the Atlantic and gain some strength.”

Tweet This Click to share quote on Twitter: "It started out in the Cape Verde region," Masson explained. "It formed so far out there in the tropical warm waters, and it has had all this time to cross the Atlantic and gain some strength."

Hurricanes gain their energy from the ocean, Masson explained, which is why it continued to build for days as Irma travelled to where it is now.

WATCH: Ongoing coverage of Hurricane Irma

0:54 People fleeing Hurricane Irma cause traffic jam on highway out Florida

• People fleeing Hurricane Irma cause traffic jam on highway out Florida
• Hurricane Irma causes havoc in Caribbean
• Barbuda devastated by Hurricane Irma
• Images from space show size of massive Hurricane Irma
• Calgarians evacuated from the Dominican Republic as Hurricane Irma intensifies
• Hurricane Irma hitting British Virgin Islands, Puerto Rico
• Florida residents brace for Irma’s impact
• Predicting where Hurricane Irma will hit when it reaches the U.S.
• Trump says Irma ‘largest’ Atlantic hurricane ‘in recorded history’
• Amateur video shows Hurricane Irma hitting Virgin Islands
• Trump on Hurricane Irma: ‘Not good’
• Hurricane Irma still tracking towards Florida and U.S. east coast
• Hurricane Irma slams into Carribean island of St. Maarten
• Hurricane Irma batters Caribbean island of St. Maarten
• Hurricane Irma’s punishing winds make landfall on Antigua

Previous Video

Next Video

A second factor is warming waters.

Hurricanes need at least 26.5 C degree water to evolve. The water temperature in the Caribbean where Irma was was 30-32 C.

It’s worrisome, Masson says,  because over the past few years, the oceans have not been able to get as cold as they used to in the winter.

“What’s a bit frightening is that we’re seeing hurricanes forming outside of the designated hurricane season. Typically, we state that the Atlantic hurricane season runs from June 1 to Nov. 30, but in recent years we’ve seen a few hurricane’s forming in January, and even February,” she said.

Linked to Climate Change?

She says the fact that sea surface temperatures are continuing to rise, it “just goes to show that there’s something wrong with our temps in the ocean and it could be linked to climate change.”

Other climate scientists agree.

“Unfortunately, the physicality is very clear: Hurricanes get their destructive energy from the warmth of the ocean, and the region’s water temperatures are super elevated,” Anders Levermann, a climate scientist with the Potsdam Institute for Climate Impact Research, told Bloomberg.

Can it happen again?

“It’s not out of the question,” Masson explained.

She says this season there’s expected to be about three-four major hurricanes, but there’s no telling how strong they’ll be right now, since you need the specific conditions to get to a Category 5.

But with the possibility of more hurricanes than average in the future, there’s a higher risk for more intense storms.

*with a file from the Associated Press