Typhoon preparedness in the Marianas begins

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(CNMI Office of Homeland Security and Emergency Management) — June 1 marks the start of typhoon preparedness in the Marianas. The months of June through November are commonly known as typhoon season but that is misleading as typhoons can occur throughout the year in the western North Pacific. July through November is the time frame in which most tropical cyclones occur, with a peak in activity between September and November.

Tropical cyclones

A tropical cyclone is an all-inclusive term that is used to discuss tropical depressions, tropical storms, typhoons and super typhoons. A tropical depression is the weakest with maximum sustained winds of less than 38 mph. A tropical storm is a more intense cyclone with maximum sustained winds of 39 to 73 mph. A typhoon has maximum sustained winds of 74 mph and greater, spread across 5 categories of intensity. A typhoon becomes a super typhoon when maximum sustained winds are 150 mph or greater.

Triple threat

Tropical cyclones are dangerous because they pose a triple threat: wind, waves, and water. The intensity of tropical cyclones is based on their wind speeds. As tropical cyclone winds increase, the likelihood for widespread damage increases. The second threat are large waves. Dangerous surf and storm surge accompanying cyclones can affect vulnerable coastal areas. Finally, torrential rains as sociated with tropical cyclones can produce flash flooding and mudslides-even with a tropical depression. Keep in mind, all these can happen well before or well after the closest point of approach.

Warning process

The National Weather Service issues tropical storm watches/warnings and typhoon watches/warnings when a tropical cyclone approaches an island. Watches and warnings are based on the onset of damaging winds, 39 mph. A tropical storm/typhoon watch is issued when damaging winds are possible within 48 hours. A tropical storm/typhoon warning is issued when damaging winds are expected within 24 hours. Watches and warnings can be issued for a tropical depression if it is forecast to intensify into a tropical storm or typhoon by the time it reaches an island. Conditions of Readiness or "COR" are set by the governments of Guam and the CNMI and are closely related to NWS watches and warnings.


Preparedness is easier when there is no storm threat. Now is the time to prepare. Make sure your home and office preparedness plans and emergency kits are up to date.

Visit the following links for the latest information:


The CNMI Office of Homeland Security and Emergency Management also encourages residents to download its readyCNMI App available for free in the Apple Store or Google PlayStore to receive the latest weather updates and notifications.

For more information, contact the CNMI EOC State Warning Point at 237-8000 or 664-8000.

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