Atlantic Coast at Chatham Harbor (IN MLLW)
Massachusetts — Water Level & Flood Stage
Located in Barnstable County, Massachusetts on the Atlantic Coast. Live water level data from USGS, updated every 15 minutes.
Current Water Level
Gage Height
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Streamflow
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Last Reading
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This is an NWS forecast point (LID: CHTM3). Live data may be limited. View on NWS AHPS →
Flood Stages
Major Flood
13 ft
Moderate Flood
11.5 ft
Minor Flood
9 ft
Action Stage
8 ft
Flood stages defined by the National Weather Service. Gage height data from USGS Water Resources.
What Floods at Each Level
13 ft
Significant flooding of low lying coastal areas is expected from Chatham northward along the east shore of the Cape. Immediate coastal roads will be flooded for a time near high tide and significant beach erosion is likely. Localized evacuations of the most vulnerable coastal areas may be required.
9 ft
Flooding of lowest lying coastal areas is likely. Some immediate coastal roads may be flooded nearest the time of high tide. Large swells may also produce some localized beach erosion.
Impact statements from the National Weather Service, describing what typically happens at each water level.
7-Day Water Level Chart
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Historic Crests
| Date | Stage | Flow |
|---|---|---|
| Jan 2, 2014 | 9.76 ft | — |
| Jan 2, 2014 | 9.76 ft | — |
| Feb 8, 2013 | 9.69 ft | — |
| Feb 8, 2013 | 9.69 ft | — |
| Jan 29, 2018 | 8.81 ft | — |
About This Gauge
NWS LID
CHTM3
River
Atlantic Coast
County
Barnstable, MA
Coordinates
41.6885°N, 69.9510°W
Get Flood Alerts for Atlantic Coast
StormCast monitors this gauge and sends a push notification to your phone when the water level crosses into a new flood category — even at 3 AM.
Frequently Asked Questions
What is the current water level of Atlantic Coast at Chatham Harbor (IN MLLW)?
The Atlantic Coast at Chatham Harbor (IN MLLW) gauge is maintained by USGS and reports water levels every 15 minutes. Visit this page to see the latest reading updated live, or download StormCast to get push alerts when levels rise.
What is flood stage for Atlantic Coast at Chatham Harbor (IN MLLW)?
The NWS-defined flood stage for Atlantic Coast at Chatham Harbor (IN MLLW) is 9 feet. Action stage begins at 8 feet. Moderate flooding starts at 11.5 feet, and major flooding at 13 feet.
How do I get alerts when Atlantic Coast rises?
Download StormCast free on Google Play, go to River Gauges, and add Atlantic Coast at Chatham Harbor (IN MLLW) to your watchlist. StormCast will send a push notification to your phone whenever the water level crosses into a new NWS flood category — even when your screen is off.
Where is the Atlantic Coast at Chatham Harbor (IN MLLW) gauge located?
The gauge is located in Barnstable County, Massachusetts at coordinates 41.6885°N, 69.9510°W. Data is provided by the U.S. Geological Survey and the National Weather Service.
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Source & Notes
Data provided by: US Geological Survey
- Stage may be affected by ice.
- <span style="color: #ff0000;">Please refer to our <span style="background-color: #ffff00;"><a style="color: #ff0000; background-color: #ffff00;" title="Link to CFWBOX" href="https://forecast.weather.gov/product.php?site=NWS&issuedby=BOX&product=CFW&format=CI&version=1&glossary=0">Coastal Hazard Message</a></span> for specific information regarding Coastal Flood Watches, Warnings and Advisories. Actual impacts from any coastal flooding event may vary due to factors such as rainfall, wave action, and the number of tide cycles during which there is an onshore flow. During tropical cyclones, please refer <span style="background-color: #ffff00;"><a style="background-color: #ffff00;" title="Link to TCVBOX" href="https://forecast.weather.gov/product.php?site=NWS&issuedby=BOX&product=TCV&format=CI&version=1&glossary=1">here</a></span> for additional storm surge information.</span>
- <span style="color: #ff0000;">During a Tropical Storm or Hurricane Watch or Warning, inundation mapping provided by the <span style="background-color: #ffff00;"><a style="color: #ff0000; background-color: #ffff00;" href="https://www.nhc.noaa.gov">National Hurricane Center</a></span> (go to the web site and select the storm of interest) reflects a reasonable worst case scenario. The forecast above is the total water forecast that is most likely to occur.</span>