Tracking Hurricanes

Hurricane and tropical storm positions are given in terms of latitude and longitude to the nearest one-tenth of a degree. Latitude lines run across hurricane tracking charts (maps) from left to right. longitude lines run from bottom to top. Latitude gives the north-south position on the earth's surface, longitude the east-west position. Therefore, by knowing the latitude and longitude of a storm, we can locate it on a map. As an example, try to locate 32.3 degrees north latitude and 64.8 degrees longitude. You should be very close to the island of Bermuda.

A hurricane tracking chart appears in the January issue Field Forum, and is suitable for reproduction. Larger (and more sophisticated) charts are available from commercial sources.

For example, Kornor Enterprises sells heavy-duty plastic laminated charts in various sizes. Erasable marker and instructions are included. The company has agreed to sell the charts to ARRL members at a special, reduced price: 17x22"-$12.50; 11x15" -- $10.50; and 8.5x11" -- $8.50. (Includes shipping/handling). Identify yourself as an ARRL member when ordering. Order from Kornor Enterprises, PO Box 461, Cleveland, OH 44094, American Express, VISA, and MasterCard credit cards accepted. The KORNOR map is used by the staff at the National Hurricane Center in Coral Gables, Florida.

On the KORNOR map, solid black lines are drawn for every five (5) degrees of latitude and longitude. White lines are drawn for every (1) degree. By definition, one degree of latitude is equal to 60 nautical miles. This gives us a convenient way of estimating distances on a chart. Measure the distance between any two points, then lay this distance out on one of the north-south longitude lines. Count the number of degrees of latitude and

multiply by 60 to find the distance in nautical miles. To convert to statute miles, multiply that answer by 1.15. One nautical mile equals 1.15 statute miles. One knot (nautical mile per hour) equals 1.15 statute miles per hour.

Hurricane tracking software is also available.

During major activity, storm coordinates are provided in 3- and 6-hour updates on NOAA weather radio services around the country in the 160 MHz region. Modern 2-meter FM rigs with extended receive capability cover NOAA broadcast frequencies.

Tropical Storm and Hurricane Terminology

TROPICAL DISTURBANCE: An area of showers and thunderstorms that may have a slight cyclonic (counter-clockwise) surface circulation and maintains its identity for at least 24 hours. These are very common occurrences in the tropics.

TROPICAL DEPRESSION: A storm system displaying a noticeable rotary circulation with maximum sustained wind speeds of 38 miles per hour (33 knots).

TROPICAL STORM: Displays a substantial rotary circulation with sustained winds of 39 to 73 miles per hour (34-63 knots). When reaching tropical storm strength, a storm is given a name to aid in tracking.

HURRICANE: Strong rotary circulation with sustained surface winds of 74 miles per hour (64 knots) or more. In the western North Pacific and most of the South Pacific, such storms are called Typhoons. In the Indian Ocean they are called Cyclones.

Advisories, Watches and Warnings

SMALL CRAFT ADVISORY: Alerts boaters to wind or sea conditions that might be hazardous to small boats. Usually wind speeds must be at least 20 miles per hour (18 knots). Issued when a tropical storm or hurricane moves within several hundred miles of the coast. Boaters are advised to take precautions and not venture into the open sea.

GALE WARNING: Coastal wind speeds between 39 and 54 miles per hour (34-47 knots).

STORM WARNING: May be issued when winds of 55-73 miles per hour (48-63 knots) are expected on area waters.

HURRICANE WATCH: Issued when there is a threat of hurricane conditions developing within 24 to 36 hours.

HURRICANE WARNING: Hurricane conditions with winds of 74 miles per hour or more (64 knots) and/or dangerously high tides and waves are expected within 24 hours. People within the warning area should begin to take action to protect life and property.

TORNADO/SEVERE THUNDERSTORM WATCH: Tornadoes and severe thunderstorms often develop when hurricanes and tropical storms make landfall. A watch means these storms are possible.

TORNADO/SEVERE THUNDERSTORM WARNING: Tornadoes or severe thunderstorms are occurring within the warning area.

HURRICANE DISASTER-POTENTIAL

(Saffir/Simpson) Scale

CATEGORY/ PRESSURE/ WINDS /SURGE - DAMAGE

Category 1/ 28.94"/ 74-95 MPH /4-5 ft - MINIMAL

Primarily to trees, foliage, and unanchored mobile homes. No real damage to other structures. Some small craft my be torn from moorings.

Category 2/28.50"/96-110 MPH/6-8 ft - MODERATE

Some trees blown down. Some window, door and roofing damage. Small craft torn from moorings in unprotected anchorages. Some evacuation of shoreline residences and low-lying islands.

Category 3 /27.91"/ 111-130 MPH/ 9-12 ft - EXTENSIVE

Large trees blown down. Some structural damage to small buildings. Mobile homes destroyed. Serious coastal flooding. Many small structures near coast destroyed by wind and waves. Almost all small boats torn from moorings.

Category 4/ 27.17"/ 131-155 MPH/ 13-18 ft - EXTREME

Extensive damage to roofs on many small residences. Terrain 10 feet or less above sea level flooded. Escape routes cut by rising water 3 to 5 hours before center arrives. Massive coastal evacuation required.

Category 5/ 27.16"/ 156+ MPH/ More than 18ft - CATASTROPHIC

Complete failure of roofs on residences and many commercial structures. Small buildings overturned or blown away. Massive evacuation from low ground within 5-10 miles of the coast.

Operating Guidelines

Transmit only when directed by a disaster net control station, or station in the disaster area. Major nets include:

International Assistance and Traffic Net (IATN): 14.303 MHz
Hurricane Watch Net (HWN): 14.325 MHz
Friendly Caribus Connection: 14.283 MHz

Don't clog primary disaster frequencies by trying to force H&W traffic into the disaster area. US amateurs' efforts must be directed to receiving messages from the affected area, each one having the potential of heading off numerous US-originated messages. US amateurs must listen carefully for instructions on handling H&W traffic.