Why hurricanes occur

As the warmed, moist air rises and cools off, the water in the air forms clouds. The whole system of clouds and wind spins and grows, fed by the ocean's heat and water evaporating from the surface.

Storms that form north of the equator spin counterclockwise. Storms south of the equator spin clockwise. This difference is because of Earth's rotation on its axis. As the storm system rotates faster and faster, an eye forms in the center. It is very calm and clear in the eye, with very low air pressure. Higher pressure air from above flows down into the eye.

If you could slice into a tropical cyclone, it would look something like this. The small red arrows show warm, moist air rising from the ocean's surface, and forming clouds in bands around the eye. The blue arrows show how cool, dry air sinks in the eye and between the bands of clouds. The large red arrows show the rotation of the rising bands of clouds.

When the winds in the rotating storm reach 39 mph, the storm is called a "tropical storm. Tropical cyclones usually weaken when they hit land, because they are no longer being "fed" by the energy from the warm ocean waters. A stronger high pressure will push storms further south and west. The strength and position of the Atlantic Ridge fluctuates throughout the season. Skip to content. Programming Schedule. Ahmaud Arbery Case.

Tracking the Vaccine. First Alert Weather. Astronomical Tide And River Data. Summer Weather Tips. End Zone. Veterans Day. Taking Care of Business. Morning Break. First Alert Weather Podcast. About Us. Contact Us. Antenna Tips. Latest Newscasts. Investigate TV. Gray DC Bureau. How do hurricanes form? By Dave Turley. Survival mode can kick in, and without basic needs such as food, water and shelter, people can resort to looting and violence.

Providing these basic needs is essential — once these have been met, it removes uncertainty and makes people feel at ease. This is where ShelterBox comes in. By providing emergency shelter, people can have somewhere safe and warm to stay, which makes the process of recovery a whole lot easier.

Find out more about our response to Hurricane Irma and our teams on the ground in the Caribbean. At its peak, Hurricane Irma was twice the strength of the Great Storm of — the most violent storm to ever hit the UK. Usually, people receive warning of a hurricane around three days in advance, in which time they should:.

The hurricane was the most powerful storm ever recorded in the Atlantic Ocean and Simon, along with two million other people, was exposed to winds in excess of mph. Hurricane Maria hit as a category 5 storm with winds of kmph just days later. Our ShelterBox team helped Simon rebuild the roof of his house so he could be safely sheltered once again.

He also received a ShelterKit to help him fix his broken bed. The category 5 hurricane caused catastrophic damage throughout the island. The wind reached speeds of kmph, while homes, crops and livelihoods were totally destroyed.

It was midnight. It was scary. It was a night I will never forget. We provided Amy with a tent for her and her family to stay in until they can start rebuilding their home.

Dr Lea specialises in wind storms — specifically tropical cyclones and European storms — and assessing the risk they might pose to communities. His work is vital to humanitarian organisations like ShelterBox.

By tracking and mapping tropical storms, and identifying wind speed peaks, humanitarian organisations can then focus their attention on places that are likely to be worst affected. Disasters explained: hurricanes We spoke to Dr Adam Lea to find out everything you wanted to know about hurricanes.