Where Do Hurricanes Come From?

Where might you see a deadly hurricane in Canada? The east coast? That’s a good answer. One storm in 1775 killed more than 4000 people in Newfoundland! But hurricanes can also affect regions much further inland. Hurricane Hazel, one of the deadliest storms in Canadian history, hit Toronto in 1954. 

Hurricane Hazel killed hundreds of people in Haiti. It continued along the Atlantic coast of the United States. There, it killed dozens more people. It also caused almost $300 million in damage. 

The remnants of Hurricane Hazel made it to southern Ontario. Heavy rains flooded streets and washed out bridges in Toronto. A total of 81 Canadians died in the storm. 

Hurricanes are a kind of tropical cyclone. Tropical cyclones are intense storms that form in tropical oceans. They usually start near the equator. These storms have strong, circular winds and heavy rain. 

Tropical cyclones are called different things. It all depends on where they start. Hurricanes start near the Caribbean, Mexico and Central America. Typhoons start near the Philippines, China and Japan. In the South Pacific and the Indian Ocean, these storms are just called cyclones. 

How does a hurricane form?

All tropical cyclones, including hurricanes, develop in the same way. The ocean needs to be at least 26.5 degrees Celsius for a hurricane to form. When wind blows across the warm ocean water, the warm, moist air rapidly rises. As it rises, the moist air cools and the water in it condenses into large storm clouds. The cooling water also releases a lot of heat. This heat transfer creates enough energy to cause strong winds.

These winds push even more warm air up from the ocean surface. More clouds and more wind make the storm more intense. Rapidly moving air creates an area of low pressure at the centre of the hurricane. This is called the “eye of the storm.” It’s usually very calm. However, the area around the eye has the most violent winds.

The Coriolis effect causes a hurricane to move in a circle. The rotation of the Earth makes tropical cyclones rotate clockwise in the Southern hemisphere. And it makes them rotate counterclockwise in the Northern hemisphere. Hurricanes develop north of the equator. So they all rotate counterclockwise!

Each stage of a hurricane has a different name:

• A tropical disturbance is a cluster of clouds and thunderstorms that may become a hurricane. 

• A tropical depression has wind speeds between 40 and 62 km/h. 

• Tropical storms have wind speeds over 62.5 km/h. 

• And when winds reach 119 km/h, a hurricane officially becomes a tropical cyclone. 

There are five classes of hurricanes. They’re based on the Saffir-Simpson Scale. A Class 1 hurricane may cause “some damage.” A Class 5 hurricane can cause “extreme damage.” 

When a tropical depression becomes a tropical storm, it gets a name. Atlantic hurricanes are named according to a list. It alternates between male and female names and gets updated every six years. If a storm causes significant damage, its name will be retired. For example, there will never be another hurricane named Hazel.

Did you know?

The most powerful Atlantic storm ever was Hurricane Wilma. It tore through the Caribbean and the southern United States in 2005. It had peak wind speeds of over 296 km/h!

What are some of the effects of hurricanes?

Hurricanes get their strength from warm tropical waters. They tend to die out pretty quickly when they hit land or colder waters. This is why even coastal parts of Canada don’t experience the full force of these storms. However, even weakened hurricanes can cause a lot of damage. Just ask someone who lived in Toronto, Ontario in 1954!

Along with high winds, hurricanes can bring extreme rainfall. Many storms drop hundreds of millimetres of rain on an area before moving on. Many people get trapped, or even drown. Flooding from a hurricane can also cause millions or even billions of dollars worth of damage. Storms also leave behind contaminated water that can spread disease. 

Did you know?

In 2012, Hurricane Sandy hit the northeastern United States. The storm caused widespread power outages. It also disrupted the local fuel supply chain, causing a major gasoline shortage. 

Hurricanes also affect natural environments. For example, storm surges or high waves can damage coral reefs.

But these massive storms also have some benefits. They can help to flush out wetlands and lagoons in tropical areas. This removes waste and brings in fresh water and nutrients. Hurricanes also move large masses of very warm air northward. This helps lower temperatures in tropical regions.

Hurricanes are fascinating weather systems. The more scientists learn about them, the better we can prepare for storms like Hurricane Hazel!