The fishing vessel Waterdog listing hard
to port near the entrance to Jupiter Inlet
in a shoaling sea on September 3, 2010.
Weather and marine conditions can change frequently and rapidly. Large waves, thunderstorm winds, lightning, and waterspouts are just some of the hazards that can impact marine conditions across Florida’s waterways. These hazardous conditions are mostly caused by tropical cyclones during the summer months and from strong cold fronts during the winter months, but can also be produced from everyday thunderstorm activity.
Ocean waves are generated from various sources. The most common are those created by the wind. These waves can occur over oceans, seas, lakes, and intracoastal waterways.
Waves are constantly changing and can grow quickly. Rough seas build rapidly as winds approach gale force (34 knots or 39 mph). Under these conditions, seas are likely to build to 12 feet or more. When seas build to five or six feet, small craft operation is cumbersome and could become deadly.
A Small Craft Advisory is issued by the National Weather Service when seas build to seven feet or more and small craft operators should strongly consider remaining in port.
Surf and Rip Currents
As ocean waves approach the coast, they move from the deep to shallow waters. The wave heights begin to increase due to friction along the ocean floor. Once the surf reaches a height of 10 feet or greater along the Atlantic Beaches, or a height of 5 feet or greater along the Gulf beaches, The National Weather Service issues a High Surf Advisory.
Breaking waves induce small ocean currents near the coastline that can lead to rip current development. A rip current is a powerful channel of water flowing quickly away from shore, which occurs most often at low spots or breaks in the sandbar and in the vicinity of structures such as jetties and piers. Additionally, long periods with elevated winds parallel to the coast can lead to strong along shore currents, which spawn rip currents as well. This is a common occurrence in the winter months along the Florida Panhandle beaches in the wake of strong cold fronts due to moderate to strong westerly winds.
Thunderstorm Winds and Lightning
A large waterspout near Punta Gorda,
Florida on July 15, 2005.
Thunderstorms are violent, short-lived weather disturbances that can include lightning, heavy rain or hail, and strong, gusty winds. The strong gusty winds in a thunderstorm can lead to rapidly building seas and very rough marine conditions.
Florida has the distinction of being known as the “lightning capitol of the United States”. The shape and orientation of the Florida Peninsula, combined with its location in the summer trade-wind belt and being surrounded by water, is a perfect recipe for thunderstorm development and, therefore, abundant lightning production.
Thunderstorms with frequent cloud-to-ground lightning often affect the inland lakes and rivers during the afternoon. Early morning lightning storms are more common along the coast. Lightning can strike the ground or water many miles away from the storm cloud. If you hear thunder, you are close enough to the cloud to be in danger of being struck by lightning.
The vast majority of lightning injuries and deaths on boats occur on small boats with no cabin. It is crucial to listen to weather information when you are boating. If thunderstorms are forecast, do not go out. If you are out on the water and skies are darkening, get back to land and find a safe building or safe vehicle. If this is not possible, drop anchor and get as low as possible. Boats with cabins offer a safer, but not perfect, environment for protection. However, safety is increased if the boat has a properly installed lightning protection system. If you are inside the cabin, stay away from metal and all electrical components.
A waterspout is a tornado over water. Florida. In Florida, there are two spout types of waterspouts. The “type A” spout is a violent and potentially destructive vortex which often moves quickly. These spouts often form in the spiral rainbands of approaching tropical cyclones and can also develop along or ahead of winter cold front squall lines.
The second type of waterspout, the “type B” spout, is usually less violent, slower moving, and less destructive than the type A spout. This type of waterspout develops quickly beneath a rapidly building cloud line, most often during the Florida rainy season (May–October). This type of waterspout can drift almost silently over a bay or a lagoon, and is very common during the summer along the coasts of South Florida and the Florida Keys.
Even though it is slower than a type A spout, the winds around a type B waterspout can reach and exceed 40mph, which is strong enough to swamp or capsize a small boat. ALL waterspouts pose a threat to boater safety, and should be avoided.
National Safe Boating Week is May 19-25, 2012
More information about marine hazards and what you can do to protect yourself and others can be found at http://www.weather.gov/os/marine/safeboating or http://www.floridadisaster.org.
How to Obtain Marine Weather Information
- NOAA All-Hazards Weather Radio, with the broadcast available on the VHF “weather band” (channels 1–5). The U.S. Coast Guard re-broadcasts some marine weather warnings, advisories, and statements across the marine radio emergency channel.
- The Internet. Each National Weather Service forecast office serving Florida has a Website containing important local weather information.
- Smartphones have also become an increasingly popular way to obtain marine weather information. To receive marine weather information via smartphone, simply point your HTTP-enabled device (PDA) to mobile.weather.gov. Or, point your WAP-enabled device (Internet capable cell phone) to cell.weather.gov.
Always plan ahead and follow safe boating practices.
A safe and enjoyable Florida boating experience is your responsibility. Please keep the following safety actions in mind when heading out on the water:
- File a float plan before getting underway— this could be as simple as letting someone know where you are going and when you expect to be back.
- Check observed and forecast weather conditions before beginning your trip.
- Have an escape plan in mind. Thunderstorms and weather related hazards form quickly. Never let storms cut off your route back to land.
- Watch for threatening dark clouds, a steady increase in seas or an increase in wind.
- Know the limitations of your craft—if gale warnings or small craft advisories are in effect, cancel or postpone your voyage.
- Wear a life jacket.
- If lightning is threatening, keep below decks if possible and keep away from metal objects that are not grounded.
- Listen to NOAA All-Hazards Weather Radio for the latest warnings, watches, advisories and forecasts.
- If you are involved in a marine accident, do not leave your boat!
- The Coast Guard advises boaters to remain alert and observe safety and security zones at all times.