Tropical cyclones are intense low-pressure systems typically associated with:
- High winds
- Flooding due to:
- Storm surge
- Intense rainfall
Tropical cyclones vary greatly in size and intensity, making their impacts storm-dependent and difficult to fully predict. The smallest known storm was Cyclone Tracy (1974), which had a diameter of only 30 miles, nearly small enough to pass between Raleigh and Chapel Hill. The largest known storm was Typhoon Tip (1970), which grew to a maximum diameter of nearly 1,400 miles -- large enough to cover most of the western United States. However, small storms can be dangerous storms; Tracy killed 71 people when it made landfall in Australia.
In the Atlantic Ocean, hurricane season lasts from June 1st to November 30th with the peak of hurricane season in early- to mid-September. Although storms rarely form outside this season, there are exceptions: in 2007, Tropical Storm Andrea formed off the North Carolina coast in early May, and in 2005, Tropical Storm Zeta formed on December 30th and lasted into 2006.
Storms affecting North Carolina also peak in early to mid-September. However, North Carolina's proximity to the Gulf Stream and its protruding coastline make it a likely location to receive an early season (June and July) spike in tropical activity.
Tropical cyclones affecting North Carolina usually take one of three tracks:
- Coastal Track: Largest threats are high winds and coastal flooding from storm surge
- Inland Track: Usually causes nearly statewide damage from flooding and high winds
- Gulf Track: Mostly likely to cause flooding in the mountains