The National Hurricane Center (NHC) uses alert designations to communicate the potential and imminence of tropical cyclone threats to the public. These designations, specifically the Hurricane Watch and Hurricane Warning, promote public safety and facilitate timely preparedness actions. Understanding the difference between these two alerts is paramount for coastal residents and others in the path of a storm. They are issued to provide sufficient lead time for life-saving measures.
Hurricane Watch: Potential Threat and Time Horizon
A Hurricane Watch signifies that hurricane conditions, defined as sustained winds of 74 miles per hour or higher, are a possibility within a specified geographical area. This alert is issued when the threat is real but not yet certain, meaning the forecast track still contains significant uncertainty. The National Hurricane Center issues this alert 48 hours before the anticipated arrival of tropical storm-force winds, which are sustained winds between 39 and 73 miles per hour.
This 48-hour lead time is chosen because preparedness activities, such as securing outdoor items and evacuation planning, become difficult and hazardous once tropical storm-force winds begin. The Watch is intended to trigger initial preparations, signaling that residents should closely monitor the storm’s progression and finalize their emergency plans. It alerts the public to the potential for a dangerous situation without confirming the hurricane’s landfall in that specific location.
Hurricane Warning: Imminent Danger and Severity
A Hurricane Warning is the highest level of alert and is issued when hurricane conditions are expected within the defined coastal area. This designation communicates a high degree of certainty that sustained winds of 74 miles per hour or greater will impact the region. The warning is issued 36 hours before the anticipated onset of tropical storm-force winds.
The 36-hour timeframe signals that the threat is imminent, demanding the immediate execution of protective actions. The window for safe preparation is closing rapidly, as the onset of tropical storm-force winds will make it unsafe to be outdoors. The Hurricane Warning is a direct instruction to complete all necessary preparations for the storm’s arrival.
Actionable Steps Required for Each Designation
Hurricane Watch Actions
Upon the issuance of a Hurricane Watch, the public should immediately begin the preparatory phase of their emergency plan. This is the time to gather and organize emergency supplies, including non-perishable food, water, and first-aid items. Residents must also ensure vehicles are fueled and secure any loose outdoor items, such as patio furniture and garbage cans. These items could otherwise become dangerous projectiles in high winds.
Hurricane Warning Actions
When a Hurricane Warning is issued, the focus must shift from preparation to protection and the execution of established plans. All preparations, including boarding up windows or deploying storm shutters, must be completed promptly. If local officials issue an evacuation order, residents must immediately follow the designated evacuation routes to safer locations. Those advised to shelter in place should move to an interior room on the lowest floor of their structure, away from windows. They should also be prepared to turn off utilities if instructed to do so by authorities.