“IRMA TAKING ITS TIME MOVING AWAY FROM CUBA. LIFE-THREATENING STORM SURGE EXPECTED IN THE FLORIDA KEYS AND THE WEST COAST OF FLORIDA …”
The National Weather Service issued the bulletin at 11 p.m. Sept. 9, 2017. The NWS conveyed the message, concisely, quickly to those tasked with monitoring storms, reporting the weather and coordinating emergency responses.
The message also reached many people who evacuated Anna Maria Island the day before the storm, which did not directly hit the island but still caused flooding, power outages and property damages, including to the historic Anna Maria City Pier.
Hurricane season novices departed the island ahead of Irma but also seasoned islanders who heeded National Hurricane Center advisory that warned “Irma is a potentially catastrophic Category 5 hurricane and will bring life-threatening wind, storm surge and rainfall hazards.”
Understanding terminology in such an advisory, as well as forecast models and tracking charts is key to being storm ready.
So a look at some of the terms and acronyms the NWS and other agencies use during the hurricane season:
- Category: Hurricanes are classified in terms of intensity, from Category 1 to Category 5, with 5 being the most intense.
- Coastal flood warning: A warning to expect significant wind-forced flooding along low-lying coastal areas.
- Coastal flood watch: An alert to expect significant wind-forced flooding along low-lying coastal areas.
- Cone of uncertainty: The tracking model that shows the probable path of the storm center but not the size of the storm.
- EOC: The emergency operations center that serves as a central location for the coordination and control of all emergency preparedness and response activities.
- Evacuation time: The lead-time that a populated coastal jurisdiction must have to relocate residents of vulnerable areas from an approaching hurricane.
- Eye: The relatively calm area near the center of the hurricane, where winds are light, and the sky is often partly covered by clouds.
- Eye landfall: The point in time when the eye, or physical center of the hurricane, reaches the coastline from the hurricane’s approach over water.
- Flood warning: Indicates the expected severity of flooding, as well as where and when the flooding will occur.
- Forward speed: The rate of movement of the hurricane eye in miles per hour or knots.
- Gale warning: Is defined as sustained winds within the range of 39-54 miles an hour (34-47 knots), either predicted or occurring. Gale warnings generally are not issued during tropical cyclone situations.
- Hurricane: The term for when winds reach a constant speed of 74 mph or more. These winds blow in a large spiral around a relatively calm center of extremely low pressure known as the eye of the hurricane.
- Hurricane advisory: A notice describing the present and forecast position and intensity of the storm.
- Hurricane track: The line of movement of the eye through an area.
- Hurricane warning: An alert added to a hurricane advisory to expect hurricane conditions within 24 hours.
- Hurricane watch: An alert added to a hurricane advisory covering a specified area and duration. A hurricane watch means hurricane conditions are a real possibility; it does not mean they are imminent.
- Public shelter: Generally, a public school or other such structure designated by county officials as a place of refuge.
Tropical cyclone: Low-pressure systems that include thunderstorms and rotate counterclockwise. - Tropical depression: A tropical cyclone with winds of 38 mph or less.
Tropical storm: A tropical cyclone with winds of 39-73 mph. - SLOSH: A computerized model — sea, lake and overland surges from hurricanes — which can estimate the overland tidal surge heights and winds that result from hypothetical hurricanes with selected characteristics in pressure, size, forward speed, track and winds.
- Storm surge: The high and forceful dome of wind-driven waters sweeping along the coastline near where the eye makes landfall or passes close to the coast.