Weatherz School: Hurricanes

Hurricane Ian slammed into Florida with a deadly storm surge, devastating wind damage, and catastrophic flooding. Violent tropical storms like this one are powerhouse weather systems that form when the right conditions fall into place.

A key ingredient for tropical storm development is warm waters. The ocean temperature must be at least 80 degrees for a depth of 150 feet. This is the fuel for a hurricane, but a storm doesn’t begin to develop until a low pressure system interacts with the warm water.

Hurricanes often begin with a tropical wave, which is a low pressure area that moves along the trade winds. Low pressure can also develop from converging winds forcing upward motion. If low pressure forms over warm enough water in a moisture rich atmosphere, thunderstorm development will soon follow.

In order for our hurricane to continue to grow, we need upper level winds to blow in generally the same direction. In other words, we need low wind shear. If the winds change a lot in speed and direction, it can weaken the tropical storm. Even when all of these factors come together, a hurricane doesn’t always develop.

Dust in the atmosphere can be a non-starter. Dust from the Saharan Desert can be picked up by winds and carried far to the west through the tropics. Remember our tropical ingredients, warm water and moisture? Dust causes some of the incoming sunlight to be reflected. Less sunlight leads to cooler ocean temperatures. And the dry Saharan air takes away our moisture.

Hurricane Ian’s destruction is a sobering reminder of how devastating tropical storms can grow to be when the environment is favorable.