UK warns against travel as Storm Floris hits the country

Storm Floris is battering the UK with winds reaching 145 km/h (90 mph), triggering a yellow weather warning for millions in northern regions. Authorities warn that an amber alert may soon follow, as conditions intensify.

Meteorologists point to Storm Floris as yet another sign of increasingly powerful and destructive natural phenomena worldwide. But even the most ferocious of storms have a soft spot, a region in the center of all that swirling cloud that remains calm and clear and free of the most severe weather. This is the eye of the storm, a phenomenon that still baffles scientists and has yet to be fully explained. But how does an eye occur, and why are some people prepared to fly an aircraft through the most extreme of weather conditions to reach it?

For an explanation, click through this gallery for some eye-popping facts.

What is a hurricane?

In appearance, a hurricane resembles a colossal whirlpool, a gigantic mass of revolving air. But how exactly do hurricanes and other tropical storms form, and why do they have an eye?

Storm characteristics

Hurricanes are typically marked by wind speeds over 74 mph (119 km/h), and a circular rotating motion with a clear, low pressure center: the eye.

Origins of storms

These storms are called hurricanes when they originate over the Atlantic Ocean and typhoons or tropical cyclones when they form elsewhere. However, when a storm's maximum sustained winds reach 74 mph, it is often just referred to as a hurricane.

Warm water and wind

In order to come to life, a hurricane needs two basic ingredients, namely warm water and wind. It begins to take shape from a cluster of thunderstorms that suck up the warm, moist air and move it high into Earth's atmosphere.

Cycling of air

The winds and storm system spin because of this cycling of the air. But momentum is also achieved by something called the Coriolis effect.

Winds of change

For example, due to the Coriolis effect hurricanes in the Northern Hemisphere spin in a counterclockwise direction, while hurricanes in the Southern Hemisphere (known as cyclones) spin in a clockwise direction. And the greater the speed of the hurricane's rotation, the greater the strength of the Coriolis effect.

Seeing into the eye

The eye is roughly circular in shape, typically 19–40 miles (30–65 kilometers) in diameter. It is surrounded on all sides by the storm.

The eyewall

The barrier between the storm and the eye is called the eyewall. This is a ring of towering thunderstorms where the most ferocious weather and highest winds of the storm occur. It's the most devastating region of any hurricane.

Size matters

Generally speaking, the more powerful the hurricane the smaller the eye tends to be.

The cause of eye formation

The cause of eye formation is still not fully understood. One theory is that the Coriolis effect causes wind to be deflected from the center of the storm, creating the calm eye.

Air speed factor

Most experts agree that the eye is  probably related to the conservation of angular momentum combined with centrifugal force. In science speak, conservation of angular momentum means that objects will spin faster as they move toward the center of circulation. In other words, air increases its speed as it heads toward the center of a hurricane or tropical cyclone.

Hurricane hunters

Hurricane hunters are aircrews that deliberately fly into hurricanes and tropical cyclones to collect data. The Lockheed WP-3D Orion (pictured) is the NOAA's primary hurricane research platform, capable of flying directly through the hurricane's eyewall and conducting various experiments requiring flight patterns in various parts of the storm.

Air reconnaissance

The NOAA also use a modified Gulfstream G-IV jet as a preliminary reconnaissance vehicle to survey storm patterns. In this 2005 image, the aircraft is passing the eyewall on the backside of Hurricane Rita.

Center of the storm

This similar view of Katrina's eyewall includes the aircraft's antenna, used for collecting weather information.

Satellite tracking

Satellites use infrared imagery to help meteorologists identify the areas of the greatest intensity within large storm systems, such as the areas with the most intense convection, known as overshooting cloud tops (dark orange), surrounding the eye and along the outer bands.

The effects of climate change

Hurricane Helene, which struck the Southeastern United States in late September 2024, is the latest in an increasingly catastrophic series of tropical storms to make landfall around the world. But how does climate change relate to this increase in hurricane strength?