How hurricanes like Michael form

Shayanne Gal/Business Insider
  • Hurricane Michael is expected to hit Florida’s Gulf Coast early this afternoon.
  • Hurricanes form near the equator, driven by warm ocean water.
  • As humans warm up the atmosphere by burning fossil fuels, hurricanes are getting slower, wetter, and more dangerous.

The bands of Hurricane Michael, a major Category 4 storm, are hitting the Gulf Coast of Florida. Its eye is expected to make landfall imminently, and Michael could be the most destructive storm to hit Florida’s Panhandle in decades.

“THIS IS A WORST CASE SCENARIO for the Florida Panhandle!! Listen to your local emergency officials. Stay Inside & Survive!”NWS Director Dr. Louis Uccellini tweeted Wednesday.

Given its extremely low central pressure – 923 mb as of 11 a.m. – Michael could be one of the strongest hurricanes ever to hit the US. (Hurricane Andrew’s was 922 mb and Katrina’s was 920 mb.)

Hurricanes are vast, low-pressure tropical cyclones with wind speeds over 74 mph.

In the Atlantic Ocean, the hurricane season generally runs from June 1 through November, with the peak of storm activity occurring around September 10. The storms form over warm ocean water near the equator, when sea surface temperature is at least 80 degrees, according to The National Hurricane Center.

As warm moisture rises, it releases energy, forming thunderstorms. As more thunderstorms are created, the winds spiral upward and outward, creating a vortex. Clouds then form in the upper atmosphere as the warm air condenses.

As the winds churn, an area of low pressure forms over the the ocean’s surface. At this point, hurricanes need low wind shear – or a lack of prevailing wind – to form the cyclonic shape associated with a hurricane. Once the wind speed hits 74 mph, the storm is considered a Category 1 hurricane on the Saffir-Simpson scale.

Saffir simpson hurricane scaleSamantha Lee/Business Insider

Hurricanes use warm water as fuel, sucking up moisture and expanding outward. But when the storm moves over colder water or land, it dissipates.

Because climate change is causing ocean and air temperatures to climb, hurricanes are getting stronger, wetter, and more sluggish.

Recent research from the National Oceanic and Atmospheric Administration found that storms slowed by an average of 10% between 1949 and 2016, making storm surges and the associated flooding more costly and disastrous. On top of all this, sea-level rise also increases the flood risk from hurricanes.

Although it remains to be seen how Hurricane Michael will play out in the US, the storm killed at least 13 people in Central America after its torrential downpours caused flash flooding, according to Reuters.

NOW WATCH: Briefing videos

Business Insider Emails & Alerts

Site highlights each day to your inbox.

Follow Business Insider Australia on Facebook, Twitter, LinkedIn, and Instagram.