CoastWarn
NOAA coastal flood alerts
Only for iPhone
Free · In‑App Purchases
iPhone
CoastWarn monitors official NOAA water-level data and alerts you when observed levels reach the threshold you set.
If you live, work, or keep a boat on the coast, you know the drill: nuisance flooding that soaks your car, a dock line that needs more slack, a driveway that disappears at high tide. CoastWarn helps you keep track of the water levels that matter to you.
HOW IT WORKS
- Find a supported NOAA station using your ZIP code or the station map.
- Set the water-level threshold that matters to your property or boat.
- Receive flood alerts and all-clear notifications, with current readings and trends.
- See “Flood Expected” notices when supported regional forecasts predict your threshold will be reached.
BUILT FOR COASTAL REALITY
- Official NOAA CO-OPS water-level observations and tide predictions.
- Adjustable alert thresholds at eligible stations.
- Time-sensitive notifications for minor-or-higher flood alerts, subject to your iPhone’s notification settings.
- Tide charts and regional model projections where available.
- Alert history, monitoring status, and notices when monitoring is interrupted.
WHO IT’S FOR
Waterfront homeowners · boaters and marina tenants · coastal businesses · anyone who lives with a rising tide
TRY IT FREE
CoastWarn is free for 7 days. Continue with CoastWarn Pro Lifetime: a single $19.99 purchase that unlocks the app’s features with no subscription or renewal. No user account required. Restore Purchases is available in Settings.
Data, forecasts, and alert monitoring vary by station. Alert delivery depends on current data, connectivity, notification permissions, and iOS scheduling. CoastWarn supplements official warnings; always follow National Weather Service guidance and local emergency instructions.
Ratings & Reviews
- This app hasn’t received enough ratings or reviews to display an overview.
Flood alerts
- Alert details now show when NWS says the hazard ends, and say "Ended" once it has.
- When NWS gives no end time, the app shows when NWS will next update the alert.
- Alert details now include the NWS instructions (precautionary and preparedness actions) whenever NWS sends them.
- NWS text keeps its tide tables and road lists laid out as NWS wrote them.
Tides
- High and low tide rows show the forecast peak, so they match your flood alert. When the forecast peak differs from the NOAA tide table by 15 minutes or more, the row shows the tide table time too.
- A tide that has already peaked no longer shows as the next high.
- Chart time labels no longer overlap.
Fewer false alarms about monitoring
- Water level gauges often report 12 to 18 minutes late. CoastWarn now waits until a reading is 45 minutes old before it warns you about a missed update or shows the reading's age. Notices during an active flood alert are never delayed.
The developer, Ryan Dean, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Linked to You
The following data may be collected but it is not linked to your identity:
- Identifiers
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Ryan Dean
- Size
- 3 MB
- Category
- Weather
- Compatibility
Requires iOS 17.0 or later.
- iPhone
Requires iOS 17.0 or later.
- iPhone
- Languages
- English
- Age Rating
4+
- 4+
- In-App Purchases
Yes
- CoastWarn Lifetime Unlock $19.99
- Copyright
- © MemoryForge, LLC
