Tropical Cyclone is a generic term referring to a storm that forms in tropical regions that is essentially a “warm-core” storm without fronts or other weather features associated with it. In the Central Pacific there are three types of tropical cyclones, each defined by their associated wind speeds.
Tropical Depression – Winds up to 38 mph and designated by a number (ex. TD-01)
Tropical Storm – Winds of 39 to 73 mph and designated by a name
Hurricane – Winds equal to or greater than 74 mph and designated by a name. Hurricanes are broken down further into five categories of increasing wind threat with category 5 being the strongest.
On average 4 to 5 tropical cyclones form in or travel through the Central Pacific ocean during the calendar year. Records indicate that one-third of these cyclones reach hurricane strength, one-third reach only tropical storm strength, and the final one-third only reach tropical depression strength.
Since 1970 tropical cyclones have impacted the Central Pacific each month of the year, excluding February and May. The peak time of occurrence is July through October, with the most common occurrence during August. Of the 177 tropical cyclones in the Central Pacific since 1970, 167 occurred during the July through October time frame.
Hawaii is certainly not immune to direct impacts from tropical cyclones. Three hurricane landfalls have occurred since 1950: Hurricane Dot (1959), Hurricane Iwa (1982), and Hurricane Iniki (1992). Each of these hurricanes brought very significant damage in their wake.
In Hawaii, mountainous terrain accelerates hurricane and tropical storm winds causing extremely high winds that can destroy buildings, structures, trees, vegetation and crops.
Heavy and prolonged rains can accompany all types of tropical cyclones including hurricanes, tropical storms, and tropical depressions. Even the weakest tropical depressions can bring torrential rains and flash flooding to the Hawaiian Islands.
When forming a disaster preparedness plan, consider each factor and how it could affect your family and property.
Understanding the difference between National Weather Service watches and warnings is critical to being prepared for any dangerous weather hazard, including hurricanes.
A hurricane watch lets you know that weather conditions are favorable for a hazard to occur. It literally means "be on guard!" During a weather watch, gather awareness of the specific threat and prepare for action - monitor the weather to find out if severe weather conditions have deteriorated and discuss your protective action plans with your family.
A hurricane warning requires immediate action. This means a weather hazard is imminent - it is either occurring (a tornado has been spotted, for example) - or it is about to occur at any moment. During a weather warning, it is important to take action: grab the emergency kit you have prepared in advance and head to safety immediately. Both watches and warnings are important, but warnings are more urgent.
A short video of Hurricane Iniki and the damage it caused.
The 2013 Hawai'i Homeowners Handbook has a great deal of information on preparing your home and your family for a Hurricane or other natural disaster.
Getting ready is as simple as recognizing hazards, gathering information, developing a plan, putting together a kit, and preparing your home. Take it one step at a time and before you know it, you will be ready.
- Gathering Information: Find the latest info on tropical cyclone hazards in Hawaii by going to the NWS Honolulu’s preparedness page as well as www.getreadyhawaii.org.
- Developing a Plan: Answer questions like – who do you contact? Where is the nearest shelter? Where is our family/business meeting place? Where do I find information? Where are our escape routes?
- Disaster Kit: Have enough non-perishable food and water for you and yours for at least 7 days. Keep 10 days worth of medication on hand, and make copies of important documents. Have what you need to survive without power, while staying comfortable. A list of recommended supplies.
- Prepare Your Home: Reinforce your roof with hurricane clips and protect your windows with shutters and/or plywood (This will also save you money on your hurricane insurance!). Pick up and store loose items in and around your home.