(CNN) The National Hurricane Center is urging people in the Bahamas to stay inside as the eye — the calmest part of the storm — passes over.
"This is a life-threatening situation," the center said in a 9 p.m. ET update. "Do not leave your shelter as the eye passes over, as winds will rapidly increase on the other side of the eye."
Some background: The eye is the center of the storm. It is the calmest part of the storm, and if you're in it, you can even see blue sky during the day and stars at night.
However, the eyewall, which surrounds the eye, is the most dangerous portion of the storm. This is the only area where you will find the winds that are the "strength" of the hurricane, or maximum winds.
This chart shows the anatomy of a hurricane:
Here's some hurricane terminology you might want to know.
Eye: The center of the storm. If you are in the eye, you can see the stadium effect -- where the clouds stack up like a stadium. It is the calmest part of the storm. You can even see blue sky during the day and stars at night.
Eye wall: This is the most dangerous portion of the storm. This is the only area where you will find the winds that are the "strength" of the hurricane, or maximum winds.
Hurricane force winds: Hurricane force winds weaken the farther you move away from the eye. In just a few miles you can drop a whole category.
Tropical storm force winds: Tropical storm force winds usually are felt throughout a large swath of a hurricane. But they don't stretch as far as the outer edge of the clouds. These winds are still dangerous but are not the worst of the storm.
Outer bands: These are bands that spiral out of the storm like a pinwheel with water on it. These lines of storms are where tornadoes typically form. It is also where flooding can occur. The bands can create a "training" effect where it just continues to rain in the same place, like we saw in Houston for days after Harvey.
Saffir Simpson Hurricane Wind Scale
This is the scale used to measure how strong a hurricane is.
Category 1: Winds 74 to 95 mph (Minor damage)
Category 2: Winds 96 to 110 mph (Extensive damage -- Can uproot trees and break windows)
Category 3: Winds 111 to 129 mph (Devastating -- Can break windows and doors)
Category 4: Winds 130 to 156 mph (Catastrophic damage -- Can tear off roofs)
Category 5: Winds 157 mph or higher (The absolute worst and can level houses and destroy buildings)