Emergency Management

Nantucket Alerts

CivicReady is a communication service that sends immediate alerts to Nantucket's residents who are subscribed to the system.

All users will have the ability to customize their notification preferences after signing up. Alerts can be sent via email, text, and/or phone call so you never miss important communication about an emergency event in the area. We will contact you through CivicReady in the event of an emergency or other routine events based on your subscription preferences.

Nantucket Alerts! (sign up here)

Hurricane Season

The Atlantic hurricane season runs from June 1st to November 30th, The Atlantic basin includes the Atlantic Ocean, Caribbean Sea, and Gulf of Mexico.

Tropical cyclone: A rotating, organized system of clouds and thunderstorms that originates over tropical or subtropical waters and has a closed low-level circulation. Tropical cyclones rotate counterclockwise in the Northern Hemisphere. They are classified as follows:

Tropical Depression: A tropical cyclone with maximum sustained winds of 38 mph (33 knots) or less.
Tropical Storm: A tropical cyclone with maximum sustained winds of 39 to 73 mph (34 to 63 knots).
Hurricane: A tropical cyclone with maximum sustained winds of 74 mph (64 knots) or higher. In the western North Pacific, hurricanes are called typhoons; similar storms in the Indian Ocean and South Pacific Ocean are called cyclones.

Major Hurricane: A tropical cyclone with maximum sustained winds of 111 mph (96 knots) or higher, corresponding to a Category 3, 4 or 5 on the Saffir-Simpson Hurricane Wind Scale.

2023 Updated Hurricane Outlook (August 10th)

Due to current ocean and atmospheric conditions, such as record-warm sea surface temperatures, NOAA’s Climate Prediction Center—a division of the National Weather Service—has increased their prediction for the ongoing 2023 Atlantic hurricane season to an “above normal” level of activity from a “near normal” level with their most recent update.

The outlook now includes a 70% chance of 14-21 named storms, of which 6-11 could become hurricanes, and 2-5 could become major hurricanes. The updated outlook also states that current conditions are likely to counterbalance the usually limiting atmospheric conditions associated with the ongoing El Niño event.

Although cyclone formation can occur any time of the year, the Atlantic Hurricane Season officially runs from June 1 through November 30, when most tropical cyclones tend to form in the Atlantic.

NOAA satellites monitor the Nation's weather, including watching for tropical cyclone activity, 24/7. They provide vital information for forecasting hurricanes and monitoring the location, movement and intensity of storms. Geostationary satellites continuously view the entire Atlantic basin to provide real-time tracking and monitoring of tropical cyclones as well as the environmental conditions that cause them to form.

By imaging a storm as often as every 30 seconds, these satellites help forecasters more easily discern the movement of cloud features and provide greater confidence in estimating the center of the storm. NOAA satellites also provide a detailed look at the storm properties of a hurricane, including cloud top cooling, central pressure, and convective structures as well as specific features of a hurricane’s eye, wind estimates, and lightning activity. This information is critical to estimating a storm’s intensity.

NOAA’s Polar Satellite System captures data over each spot on Earth twice a day. They measure the state of the atmosphere by taking precise measurements of sea surface temperatures and atmospheric temperature and moisture, which are critical to securing storm forecasts several days in advance. These systems provide data that are particularly useful in helping forecasters predict a hurricane’s path 3 to 7 days out.

The National Hurricane Center provides the latest information on tropical storm and hurricane activity. NOAA’s Live Hurricane Tracker is a map-based page with current information.

Source: National Oceanic Atmospheric Administration (NOAA)