The mature hurricane has several significant features. See Figure 4. They include:

• Eye: Area of light winds in the center of the storm, average diameter is 10 to 30 miles.
• Eye Wall: Cloud-filled area around the eye with heaviest rainfall. Just outside the eye wall is the area of most violent winds.
• Area of Hurricane Force Winds: Area in the storm where sustained winds are expected to be over 64 knots (74 mph).
• Area of Tropical Storm (Gale) Force Winds: Sustained winds in this area exceed 34 knots (39 mph). Most of the damage caused by the storm is contained in this area. Therefore, by tracking the area of gale force winds with the position and heading of the storm, one would be relatively certain if they were threatened.
• Spiral Bands: Bands of cumulonimbus clouds spiraling inward toward the center. Heavy rainfall is contained in these bands. A typical hurricane usually has up to seven spiral bands.
• Forward Speed and Heading: The speed and direction of movement of the storm.
• Track: Storm path usually determined by past eye position. In most hurricane advisories, the latitude and longitude of the eye is given.
• Maximum Sustained Winds: Strongest windspeed averaged over one minute, occurring in the storm.