A slideshow of images from a flood event in northern New England in late December. Significant flooding occurred in Maine and New Hampshire from a combination of rainfall and snowmelt.
New England Flood Information Active
By New England Water Science Center
November 25, 2020
The USGS delivers continuous streamflow, stage (water-level), and tide data to help emergency managers and other decision makers protect life and property caused by floods and other water-related hazards.
December 2023 Flooding in Maine
December 2023 Flooding in Maine
USGS captures critical data during recent flood in Maine.
Sources/Usage: Public Domain. View Media Details
The USGS New England Water Science Center maintains nearly 450 streamgages that collect data to determine the amount of water flowing in rivers and streams in Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont. The Water Science Center also maintains about 15 tide gages along the coast of New England.
Nationwide, the USGS operates and maintains about 8,000 streamgages, which deliver near real-time data to the public.
Automatic alerts can be sent to mobile devices when streamflow of river or tide stage (water levels) reach user defined thresholds, such as a National Weather Service defined flood stage. These alerts help emergency managers and the public assess potentially hazardous conditions nearby a streamgage, stage-only gage, or tide gage.
USGS WaterNow sends data showing current water conditions directly to your mobile device.
USGS WaterAlert automatically sends email or SMS text messages when certain parameters at a USGS real-time data-collection station, exceed user-defined thresholds.
USGS Flood Information provides additional information about USGS flood science.
Sources/Usage: Some content may have restrictions. View Media Details
Current Flood Data for New England
- National Water Dashboard for New England
- WaterWatch Map of flood and high flow condition (select a State or Water-Resources Region)
- WaterWatch Map of flood and high flow conditions – New England
- USGS Project Alerts – Flood and Drought
- USGS Flood-Event Viewer (Data for Selected Current and Historic Floods – Coastal and Riverine)
- USGS Flood Inundation Mapper
- USGS Operational Total Water Level and Coastal Change Viewer
Current Streamflow, Stage, and Tide Data for New England
Sources/Usage: Public Domain. View Media Details
Flood Frequency Information
Visit USGS Floods and Recurrence Intervals for more information about floods and the annual exceedance probability (AEP).
New England Flood Frequency Studies
Sources/Usage: Public Domain. View Media Details
Flood Resources from Partner Agencies
Federal Emergency Management Agency (FEMA)
National Weather Service (NWS)
- NWS Northeast River Forecast Center
- NWS Current Precipitation Radar
- NWS Future Quantitative Precipitation Forecasts (1-7 day totals)
- NOAA Office of Water Prediction – National Water Model
Northeast River Forecast Center (NERFC)
- NERFC Daily Hydrometeorological Briefing
- Recent NERFC Observed Precipitation Maps
- NERFC 5-Day Significant River Flood Outlook
- NERFC Future Quantitative Precipitation Forecast (72 Hours)
State Emergency Management
U.S. Army Corps of Engineers
- U.S. Army Corps of Engineers – New England Reservoir Control Center
- U.S. Army Corps of Engineers Silver Jackets Program
Safety Related Resources
Below are resources associated with flood information.
USGS Flood Information
The USGS collects flood data and conducts targeted flood science to help Federal, State, and local agencies, decision makers, and the public before, during, and after a flood. Our efforts provide situational awareness, drive predictive models, inform infrastructure design and operation, undergird floodplain mapping, assist flood constituent/load quantification, and facilitate flood impact...
Rapid Deployment Gages (RDGs)
Rapid Deployment Gages (RDGs) are fully-functional streamgages designed to be deployed quickly and temporarily to measure and transmit stream stage data in emergency situations.
Surge, Wave, and Tide Hydrodynamics (SWaTH) Network
During large coastal storms, the storm surge and waves are the main cause of destruction and landscape change, transporting saline water, sediment, and debris inland. The USGS, in collaboration with stakeholders, has constructed a national Surge, Wave, and Tide Hydrodynamics (SWaTH) Network for the Atlantic, Eastern Pacific, and Central Pacific. SWaTH monitors and documents the height, extent, and...
Historical Flooding
The USGS provides practical, unbiased information about the Nation's rivers and streams that is crucial in mitigating hazards associated with floods. This site provides information about the USGS activities, data, and services provided during regional high-flow events, such as hurricanes or multi-state flooding events. The USGS response to these events is typically managed by the National Flood...
Flood Inundation Mapping (FIM) Program
Floods are the leading cause of natural-disaster losses in the U.S. More than 75 percent of declared Federal disasters are related to floods, and annual flood losses average almost $8 billion with over 90 fatalities per year. Although the amount of fatalities has declined due to improved early warning systems, economic losses continue to rise with increased urbanization in flood-hazard areas.
Floods: Recurrence intervals and 100-year floods
How do we know or measure if a flood that could happen tomorrow is worse than one that happened 2, 10 or 50 years ago? If heavy rain is being forecasted does that mean that rivers are going to rise and spill over their banks and flood your neighborhood? These are some of the questions that we think about when flooding or heavy rain is forecast by public media or the National Weather Service (NWS).
The 100-Year Flood
A 100-year flood happened last year so it won't happen for another 99 years, right? Not exactly. Misinterpretation of terminology often leads to confusion about flood recurrence intervals. Read on to learn more.
Development of Flood Insurance Maps in New England
FEMA has requested USGS expertise in hydraulics, hydrology, and mapping to generate flood insurance maps for New England.
Northeast Region Flood Science Capability Team
The USGS Northeast Region has been an active and competent force in flood-science through (1) maintenance of our streamgaging network to provide timely and accurate data to the National Weather Service, other federal (USACE and FEMA) and state agencies (Emergency Management Agencies), and the public in times of flood emergencies; (2) documentation of major floods; (3) involvement in the USGS Flood...
Below are multimedia items associated with flood information.
Filter Total Items: 55
December 2023 New England Flood Event
A slideshow of images from a flood event in northern New England in late December. Significant flooding occurred in Maine and New Hampshire from a combination of rainfall and snowmelt.
Measuring a High-Water Mark at the Androscoggin River in Topsham, Maine
A hydrologic technician measures a high-water mark near the Androscoggin River in Topsham, Maine days after a significant flood event in late December 2023. A combination of heavy rainfall and snowmelt prompted the flooding.
A hydrologic technician measures a high-water mark near the Androscoggin River in Topsham, Maine days after a significant flood event in late December 2023. A combination of heavy rainfall and snowmelt prompted the flooding.
High-Water Mark on Building in Anson, Maine
A hydrologic technician measures a high-water mark on a business in Anson, Maine after a significant flood event in late December 2023 flooded the Kennebec River.
A hydrologic technician measures a high-water mark on a business in Anson, Maine after a significant flood event in late December 2023 flooded the Kennebec River.
High Flows on Dead River in Northwest Somerset, Maine, Following Flood Event
A heavy rainstorm, saturated ground, and pre-existing snowpack prompted flooding in Maine in late December 2023. USGS researchers manually measured streamflows after the flood event to validate real-time streamgage data.
A heavy rainstorm, saturated ground, and pre-existing snowpack prompted flooding in Maine in late December 2023. USGS researchers manually measured streamflows after the flood event to validate real-time streamgage data.
High-Water Mark in Plymouth, New Hampshire
A hydrologic technician identifies a high-water mark at a gas station in Plymouth, New Hampshire following a flood event in late December 2023.
A hydrologic technician identifies a high-water mark at a gas station in Plymouth, New Hampshire following a flood event in late December 2023.
Flooding on Kennebec River at Calumet Bridge in Augusta, Maine
This USGS webcam footage shows the Kennebec River in Augusta, Maine, flooding after a large coastal storm hit much of the East Coast and battered New England with heavy rains and winds. USGS image.
This USGS webcam footage shows the Kennebec River in Augusta, Maine, flooding after a large coastal storm hit much of the East Coast and battered New England with heavy rains and winds. USGS image.
Kennebec River in Maine during flood
Photo taken in Hallowell, Maine on December 19, 2023, following a powerful rainstorm.
Photo taken in Hallowell, Maine on December 19, 2023, following a powerful rainstorm.
Piscataquis River in Maine during flood
Piscataquis River in Maine during flood following a powerful rainstorm. Vicinity of the USGS streamgage 01031500, Piscataquis River near Dover-Foxcroft, Maine on December 19, 2023.
Piscataquis River in Maine during flood following a powerful rainstorm. Vicinity of the USGS streamgage 01031500, Piscataquis River near Dover-Foxcroft, Maine on December 19, 2023.
Hallowell, Maine flood
The streets of Hallowell, Maine, were flooded following heavy rains that hit New England and most of the East Coast, December 18, 2023. USGS photo by Glenn Hodgkins
The streets of Hallowell, Maine, were flooded following heavy rains that hit New England and most of the East Coast, December 18, 2023. USGS photo by Glenn Hodgkins
Flooding in Downtown Augusta, Maine
The Kennebec River flooded in downtown Augusta, Maine, after a heavy rainstorm. USGS streamgage 01049320 monitors the streamflow of this area.
The Kennebec River flooded in downtown Augusta, Maine, after a heavy rainstorm. USGS streamgage 01049320 monitors the streamflow of this area.
Flood Waters Surround a Maine Streamgage
Flooding surrounds USGS streamgage 01029500 on the East Branch of the Penobscot River in Grindstone, Maine.
Flooding surrounds USGS streamgage 01029500 on the East Branch of the Penobscot River in Grindstone, Maine.
Streamgage inspection during rain event
USGS Scientist makes a gage inspection during the rain event at Nepaug River near Nepaug, Connecticut - 01187800. The 1800 cubic feet per second (CFS) measured during the powerful rainstorm was the highest measurement on record to date, according to provisional data.
USGS Scientist makes a gage inspection during the rain event at Nepaug River near Nepaug, Connecticut - 01187800. The 1800 cubic feet per second (CFS) measured during the powerful rainstorm was the highest measurement on record to date, according to provisional data.
New England Flood 2023
A look at the high waters and damage caused by a significant two-day rainfall event in New England in early July 2023. USGS researchers visited streamgages, manually captured discharge and river stage (or height), and canvassed for high-water marks in Vermont.
A look at the high waters and damage caused by a significant two-day rainfall event in New England in early July 2023. USGS researchers visited streamgages, manually captured discharge and river stage (or height), and canvassed for high-water marks in Vermont.
Flood-Damage Along Route 100 in Plymouth, Vermont
Heavy flooding, caused by two-day rainstorm in July 2023, transported boulders down a hillside to cover a resident's car and move their hot tub.
Heavy flooding, caused by two-day rainstorm in July 2023, transported boulders down a hillside to cover a resident's car and move their hot tub.
High-Water Mark at a Damaged Road in Weston, Vermont
A hydrologic technician points to a high-water mark on the building of Weston Town Offices days after a significant flood event, which damaged the adjacent road.
A hydrologic technician points to a high-water mark on the building of Weston Town Offices days after a significant flood event, which damaged the adjacent road.
Flood Damage to Cobble Ridge Road Bridge in Londonderry, Vermont
The Cobble Ridge Road Bridge in Londonderry, Vermont, along the West River was badly damaged during significant flooding precipitated by a heavy rainfall event.
The Cobble Ridge Road Bridge in Londonderry, Vermont, along the West River was badly damaged during significant flooding precipitated by a heavy rainfall event.
High-Water Mark Debris Line after Flood in Woodstock, Vermont
Sam Banas and Dale Tom located a debris high-water mark line in a field in Woodstock, Vermont. This physical evidence of flood water distance took place in the days following a heavy rainfall event that caused significant flooding.
Sam Banas and Dale Tom located a debris high-water mark line in a field in Woodstock, Vermont. This physical evidence of flood water distance took place in the days following a heavy rainfall event that caused significant flooding.
High-Water Mark Tag on a Tree-Trunk with Debris
A high-water mark tag nailed to a tree trunk with visible debris. The debris that adheres to the tree is the physical evidence of how high the flood waters rose during the flood event; when the waters recede, the debris transported by the flood waters that was floating on the top of the water sticks to the tree.
A high-water mark tag nailed to a tree trunk with visible debris. The debris that adheres to the tree is the physical evidence of how high the flood waters rose during the flood event; when the waters recede, the debris transported by the flood waters that was floating on the top of the water sticks to the tree.
High-Water Mark on Tree in Vermont
A high-water mark tag nailed to a tree in Vermont days after a flood-event in July 2023.
A high-water mark tag nailed to a tree in Vermont days after a flood-event in July 2023.
High-Water Disk Placement on the House Porch
USGS hydrologic technician pointing to a high-water disk on the house porch in Woodstock, Vermont after the historical flood in July 2023.
USGS hydrologic technician pointing to a high-water disk on the house porch in Woodstock, Vermont after the historical flood in July 2023.
Below are FAQ associated with flood information.
Where can I find flood maps?
FEMA is the official public source for flood maps for insurance purposes: FEMA’s Flood Map Service Center FEMA’s National Flood Hazard Layer NOAA is responsible for producing flood forecast maps that combine precipitation data with USGS streamflow data: National Weather Service - Advanced Hydrologic Prediction Service River Forecasts Long-Range River Flood Risk Coastal Inundation Dashboard : Real...
What are the two types of floods?
There are two basic types of floods: flash floods and the more widespread river floods. Flash floods generally cause greater loss of life and river floods generally cause greater loss of property. A flash flood occurs when runoff from excessive rainfall causes a rapid rise in the water height (stage) of a stream or normally-dry channel. Flash floods are more common in areas with a dry climate and...
What is a 1,000-year flood?
The term “1,000-year flood” means that, statistically speaking, a flood of that magnitude (or greater) has a 1 in 1,000 chance of occurring in any given year. In terms of probability, the 1,000-year flood has a 0.1% chance of happening in any given year. These statistical values are based on observed data.
How can a 1,000-year rainfall not result in a 1,000-year flood?
It comes down to a number of factors, including the pattern of movement of the rainstorm in each particular watershed, the conditions of the soil and plant matter in the watershed, and the timing of the rainstorm in one watershed versus other watersheds. For example, if the ground is already saturated before a rainstorm, much of the rain will run off into streams, but if the ground is dry, it will...
Why do the values for the 100-year flood seem to change with every flood?
The amount of water corresponding to a 100-year flood, a 500-year flood, or a 1,000-year flood is known as a "flood quantile". For instance, on a given river, the flood quantile corresponding to the 50-year flood might be 10,000 cubic feet per second (cfs) and the flood quantile corresponding to the 100-year flood might be 15,000 cfs. The estimates of the flood quantiles are calculated using...
We had a "100-year flood" two years in a row. How can that be?
The term "100-year flood" is used to describe the recurrence interval of floods. The 100-year recurrence interval means that a flood of that magnitude has a one percent chance of occurring in any given year. In other words, the chances that a river will flow as high as the 100-year flood stage this year is 1 in 100. Statistically, each year begins with the same 1-percent chance that a 100-year...
Does an increase in the 100-year flood estimate originate from climate or land-use change?
Climate variability (dry cycles to wet cycles) and land-use change play a significant role, but there is a large amount of uncertainty around the flood quantile estimates (the value of discharge corresponding to the 100-year flood), particularly if there isn’t a long record of observed data at a stream location. Learn more: The 100-Year Flood The 100-Year Flood--It's All About Chance
How are floods predicted?
Flood predictions require several types of data: The amount of rainfall occurring on a real-time basis. The rate of change in river stage on a real-time basis, which can help indicate the severity and immediacy of the threat. Knowledge about the type of storm producing the moisture, such as duration, intensity and areal extent, which can be valuable for determining possible severity of the...
How can I obtain river forecasts (flood forecasts)?
River forecasts (flood forecasts) are made by the National Weather Service River Forecast Centers and released through local Weather Service Offices. This NOAA website has a map showing the location of the forecast centers, their areas of responsibility, and by clicking into a region the location of the gages they use. The also provide a section for long-range river flood risk . The vast majority...
- Overview
The USGS delivers continuous streamflow, stage (water-level), and tide data to help emergency managers and other decision makers protect life and property caused by floods and other water-related hazards.
December 2023 Flooding in Maine
USGS captures critical data during recent flood in Maine.
Sources/Usage: Public Domain. View Media DetailsFlooding at the USGS streamgage Nashua River at Pepperell, MA (01096500) on March 17, 2010 at about 12:15 EDT at a gage height of 14.58 ft and discharge of 9,780 cubic feet per second. (Credit: Andrew Waite, U.S. Geological Survey, New York Water Science Center. Public domain.) The USGS New England Water Science Center maintains nearly 450 streamgages that collect data to determine the amount of water flowing in rivers and streams in Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont. The Water Science Center also maintains about 15 tide gages along the coast of New England.
Nationwide, the USGS operates and maintains about 8,000 streamgages, which deliver near real-time data to the public.
Automatic alerts can be sent to mobile devices when streamflow of river or tide stage (water levels) reach user defined thresholds, such as a National Weather Service defined flood stage. These alerts help emergency managers and the public assess potentially hazardous conditions nearby a streamgage, stage-only gage, or tide gage.
USGS WaterNow sends data showing current water conditions directly to your mobile device.
USGS WaterAlert automatically sends email or SMS text messages when certain parameters at a USGS real-time data-collection station, exceed user-defined thresholds.
USGS Flood Information provides additional information about USGS flood science.
Sources/Usage: Some content may have restrictions. View Media DetailsFlood flows on the Deerfield River at dam #3 at Shelburne Falls, Massachusetts during tropical storm Irene on August 28, 2011. (Credit: John Elder Robison. Courtesy of ©John E. Robison, used with permission) Current Flood Data for New England
- National Water Dashboard for New England
- WaterWatch Map of flood and high flow condition (select a State or Water-Resources Region)
- WaterWatch Map of flood and high flow conditions – New England
- USGS Project Alerts – Flood and Drought
- USGS Flood-Event Viewer (Data for Selected Current and Historic Floods – Coastal and Riverine)
- USGS Flood Inundation Mapper
- USGS Operational Total Water Level and Coastal Change Viewer
Current Streamflow, Stage, and Tide Data for New England
Sources/Usage: Public Domain. View Media DetailsFlood damage from tropical storm Irene, August 28, 2011, washed out Maxam Road bridge on the West Branch North River in Colrain, Massachusetts. (Credit: Andrew Waite, U.S. Geological Survey, New York Water Science Center. Public domain.) Flood Frequency Information
Visit USGS Floods and Recurrence Intervals for more information about floods and the annual exceedance probability (AEP).
New England Flood Frequency Studies
Sources/Usage: Public Domain. View Media DetailsFlood damage to Eunice Williams Road in Greenfield, MA on the Green River from tropical storm Irene on August, 28, 2011. (Credit: Gardner Bent, U.S. Geological Survey, New England Water Science Center. Public domain.) Flood Resources from Partner Agencies
Federal Emergency Management Agency (FEMA)
National Weather Service (NWS)
- NWS Northeast River Forecast Center
- NWS Current Precipitation Radar
- NWS Future Quantitative Precipitation Forecasts (1-7 day totals)
- NOAA Office of Water Prediction – National Water Model
Northeast River Forecast Center (NERFC)
- NERFC Daily Hydrometeorological Briefing
- Recent NERFC Observed Precipitation Maps
- NERFC 5-Day Significant River Flood Outlook
- NERFC Future Quantitative Precipitation Forecast (72 Hours)
State Emergency Management
U.S. Army Corps of Engineers
- U.S. Army Corps of Engineers – New England Reservoir Control Center
- U.S. Army Corps of Engineers Silver Jackets Program
Safety Related Resources
- Science
Below are resources associated with flood information.
USGS Flood Information
The USGS collects flood data and conducts targeted flood science to help Federal, State, and local agencies, decision makers, and the public before, during, and after a flood. Our efforts provide situational awareness, drive predictive models, inform infrastructure design and operation, undergird floodplain mapping, assist flood constituent/load quantification, and facilitate flood impact...Rapid Deployment Gages (RDGs)
Rapid Deployment Gages (RDGs) are fully-functional streamgages designed to be deployed quickly and temporarily to measure and transmit stream stage data in emergency situations.Surge, Wave, and Tide Hydrodynamics (SWaTH) Network
During large coastal storms, the storm surge and waves are the main cause of destruction and landscape change, transporting saline water, sediment, and debris inland. The USGS, in collaboration with stakeholders, has constructed a national Surge, Wave, and Tide Hydrodynamics (SWaTH) Network for the Atlantic, Eastern Pacific, and Central Pacific. SWaTH monitors and documents the height, extent, and...Historical Flooding
The USGS provides practical, unbiased information about the Nation's rivers and streams that is crucial in mitigating hazards associated with floods. This site provides information about the USGS activities, data, and services provided during regional high-flow events, such as hurricanes or multi-state flooding events. The USGS response to these events is typically managed by the National Flood...Flood Inundation Mapping (FIM) Program
Floods are the leading cause of natural-disaster losses in the U.S. More than 75 percent of declared Federal disasters are related to floods, and annual flood losses average almost $8 billion with over 90 fatalities per year. Although the amount of fatalities has declined due to improved early warning systems, economic losses continue to rise with increased urbanization in flood-hazard areas.Floods: Recurrence intervals and 100-year floods
How do we know or measure if a flood that could happen tomorrow is worse than one that happened 2, 10 or 50 years ago? If heavy rain is being forecasted does that mean that rivers are going to rise and spill over their banks and flood your neighborhood? These are some of the questions that we think about when flooding or heavy rain is forecast by public media or the National Weather Service (NWS).
The 100-Year Flood
A 100-year flood happened last year so it won't happen for another 99 years, right? Not exactly. Misinterpretation of terminology often leads to confusion about flood recurrence intervals. Read on to learn more.Development of Flood Insurance Maps in New England
FEMA has requested USGS expertise in hydraulics, hydrology, and mapping to generate flood insurance maps for New England.Northeast Region Flood Science Capability Team
The USGS Northeast Region has been an active and competent force in flood-science through (1) maintenance of our streamgaging network to provide timely and accurate data to the National Weather Service, other federal (USACE and FEMA) and state agencies (Emergency Management Agencies), and the public in times of flood emergencies; (2) documentation of major floods; (3) involvement in the USGS Flood... - Data
- Multimedia
Below are multimedia items associated with flood information.
Filter Total Items: 55
December 2023 New England Flood EventA slideshow of images from a flood event in northern New England in late December. Significant flooding occurred in Maine and New Hampshire from a combination of rainfall and snowmelt.
A slideshow of images from a flood event in northern New England in late December. Significant flooding occurred in Maine and New Hampshire from a combination of rainfall and snowmelt.
Measuring a High-Water Mark at the Androscoggin River in Topsham, MaineA hydrologic technician measures a high-water mark near the Androscoggin River in Topsham, Maine days after a significant flood event in late December 2023. A combination of heavy rainfall and snowmelt prompted the flooding.
A hydrologic technician measures a high-water mark near the Androscoggin River in Topsham, Maine days after a significant flood event in late December 2023. A combination of heavy rainfall and snowmelt prompted the flooding.
High-Water Mark on Building in Anson, MaineA hydrologic technician measures a high-water mark on a business in Anson, Maine after a significant flood event in late December 2023 flooded the Kennebec River.
A hydrologic technician measures a high-water mark on a business in Anson, Maine after a significant flood event in late December 2023 flooded the Kennebec River.
High Flows on Dead River in Northwest Somerset, Maine, Following Flood EventA heavy rainstorm, saturated ground, and pre-existing snowpack prompted flooding in Maine in late December 2023. USGS researchers manually measured streamflows after the flood event to validate real-time streamgage data.
A heavy rainstorm, saturated ground, and pre-existing snowpack prompted flooding in Maine in late December 2023. USGS researchers manually measured streamflows after the flood event to validate real-time streamgage data.
High-Water Mark in Plymouth, New HampshireA hydrologic technician identifies a high-water mark at a gas station in Plymouth, New Hampshire following a flood event in late December 2023.
A hydrologic technician identifies a high-water mark at a gas station in Plymouth, New Hampshire following a flood event in late December 2023.
Flooding on Kennebec River at Calumet Bridge in Augusta, MaineThis USGS webcam footage shows the Kennebec River in Augusta, Maine, flooding after a large coastal storm hit much of the East Coast and battered New England with heavy rains and winds. USGS image.
This USGS webcam footage shows the Kennebec River in Augusta, Maine, flooding after a large coastal storm hit much of the East Coast and battered New England with heavy rains and winds. USGS image.
Kennebec River in Maine during floodPhoto taken in Hallowell, Maine on December 19, 2023, following a powerful rainstorm.
Photo taken in Hallowell, Maine on December 19, 2023, following a powerful rainstorm.
Piscataquis River in Maine during floodPiscataquis River in Maine during flood following a powerful rainstorm. Vicinity of the USGS streamgage 01031500, Piscataquis River near Dover-Foxcroft, Maine on December 19, 2023.
Piscataquis River in Maine during flood following a powerful rainstorm. Vicinity of the USGS streamgage 01031500, Piscataquis River near Dover-Foxcroft, Maine on December 19, 2023.
Hallowell, Maine floodThe streets of Hallowell, Maine, were flooded following heavy rains that hit New England and most of the East Coast, December 18, 2023. USGS photo by Glenn Hodgkins
The streets of Hallowell, Maine, were flooded following heavy rains that hit New England and most of the East Coast, December 18, 2023. USGS photo by Glenn Hodgkins
Flooding in Downtown Augusta, MaineThe Kennebec River flooded in downtown Augusta, Maine, after a heavy rainstorm. USGS streamgage 01049320 monitors the streamflow of this area.
The Kennebec River flooded in downtown Augusta, Maine, after a heavy rainstorm. USGS streamgage 01049320 monitors the streamflow of this area.
Flood Waters Surround a Maine StreamgageFlooding surrounds USGS streamgage 01029500 on the East Branch of the Penobscot River in Grindstone, Maine.
Flooding surrounds USGS streamgage 01029500 on the East Branch of the Penobscot River in Grindstone, Maine.
Streamgage inspection during rain eventUSGS Scientist makes a gage inspection during the rain event at Nepaug River near Nepaug, Connecticut - 01187800. The 1800 cubic feet per second (CFS) measured during the powerful rainstorm was the highest measurement on record to date, according to provisional data.
USGS Scientist makes a gage inspection during the rain event at Nepaug River near Nepaug, Connecticut - 01187800. The 1800 cubic feet per second (CFS) measured during the powerful rainstorm was the highest measurement on record to date, according to provisional data.
New England Flood 2023A look at the high waters and damage caused by a significant two-day rainfall event in New England in early July 2023. USGS researchers visited streamgages, manually captured discharge and river stage (or height), and canvassed for high-water marks in Vermont.
A look at the high waters and damage caused by a significant two-day rainfall event in New England in early July 2023. USGS researchers visited streamgages, manually captured discharge and river stage (or height), and canvassed for high-water marks in Vermont.
Flood-Damage Along Route 100 in Plymouth, VermontHeavy flooding, caused by two-day rainstorm in July 2023, transported boulders down a hillside to cover a resident's car and move their hot tub.
Heavy flooding, caused by two-day rainstorm in July 2023, transported boulders down a hillside to cover a resident's car and move their hot tub.
High-Water Mark at a Damaged Road in Weston, VermontA hydrologic technician points to a high-water mark on the building of Weston Town Offices days after a significant flood event, which damaged the adjacent road.
A hydrologic technician points to a high-water mark on the building of Weston Town Offices days after a significant flood event, which damaged the adjacent road.
Flood Damage to Cobble Ridge Road Bridge in Londonderry, VermontThe Cobble Ridge Road Bridge in Londonderry, Vermont, along the West River was badly damaged during significant flooding precipitated by a heavy rainfall event.
The Cobble Ridge Road Bridge in Londonderry, Vermont, along the West River was badly damaged during significant flooding precipitated by a heavy rainfall event.
High-Water Mark Debris Line after Flood in Woodstock, VermontSam Banas and Dale Tom located a debris high-water mark line in a field in Woodstock, Vermont. This physical evidence of flood water distance took place in the days following a heavy rainfall event that caused significant flooding.
Sam Banas and Dale Tom located a debris high-water mark line in a field in Woodstock, Vermont. This physical evidence of flood water distance took place in the days following a heavy rainfall event that caused significant flooding.
High-Water Mark Tag on a Tree-Trunk with DebrisA high-water mark tag nailed to a tree trunk with visible debris. The debris that adheres to the tree is the physical evidence of how high the flood waters rose during the flood event; when the waters recede, the debris transported by the flood waters that was floating on the top of the water sticks to the tree.
A high-water mark tag nailed to a tree trunk with visible debris. The debris that adheres to the tree is the physical evidence of how high the flood waters rose during the flood event; when the waters recede, the debris transported by the flood waters that was floating on the top of the water sticks to the tree.
High-Water Mark on Tree in VermontA high-water mark tag nailed to a tree in Vermont days after a flood-event in July 2023.
A high-water mark tag nailed to a tree in Vermont days after a flood-event in July 2023.
High-Water Disk Placement on the House PorchUSGS hydrologic technician pointing to a high-water disk on the house porch in Woodstock, Vermont after the historical flood in July 2023.
USGS hydrologic technician pointing to a high-water disk on the house porch in Woodstock, Vermont after the historical flood in July 2023.
- Publications
- Web Tools
- News
- FAQ
Below are FAQ associated with flood information.
Where can I find flood maps?
FEMA is the official public source for flood maps for insurance purposes: FEMA’s Flood Map Service Center FEMA’s National Flood Hazard Layer NOAA is responsible for producing flood forecast maps that combine precipitation data with USGS streamflow data: National Weather Service - Advanced Hydrologic Prediction Service River Forecasts Long-Range River Flood Risk Coastal Inundation Dashboard : Real...
What are the two types of floods?
There are two basic types of floods: flash floods and the more widespread river floods. Flash floods generally cause greater loss of life and river floods generally cause greater loss of property. A flash flood occurs when runoff from excessive rainfall causes a rapid rise in the water height (stage) of a stream or normally-dry channel. Flash floods are more common in areas with a dry climate and...
What is a 1,000-year flood?
The term “1,000-year flood” means that, statistically speaking, a flood of that magnitude (or greater) has a 1 in 1,000 chance of occurring in any given year. In terms of probability, the 1,000-year flood has a 0.1% chance of happening in any given year. These statistical values are based on observed data.
How can a 1,000-year rainfall not result in a 1,000-year flood?
It comes down to a number of factors, including the pattern of movement of the rainstorm in each particular watershed, the conditions of the soil and plant matter in the watershed, and the timing of the rainstorm in one watershed versus other watersheds. For example, if the ground is already saturated before a rainstorm, much of the rain will run off into streams, but if the ground is dry, it will...
Why do the values for the 100-year flood seem to change with every flood?
The amount of water corresponding to a 100-year flood, a 500-year flood, or a 1,000-year flood is known as a "flood quantile". For instance, on a given river, the flood quantile corresponding to the 50-year flood might be 10,000 cubic feet per second (cfs) and the flood quantile corresponding to the 100-year flood might be 15,000 cfs. The estimates of the flood quantiles are calculated using...
We had a "100-year flood" two years in a row. How can that be?
The term "100-year flood" is used to describe the recurrence interval of floods. The 100-year recurrence interval means that a flood of that magnitude has a one percent chance of occurring in any given year. In other words, the chances that a river will flow as high as the 100-year flood stage this year is 1 in 100. Statistically, each year begins with the same 1-percent chance that a 100-year...
Does an increase in the 100-year flood estimate originate from climate or land-use change?
Climate variability (dry cycles to wet cycles) and land-use change play a significant role, but there is a large amount of uncertainty around the flood quantile estimates (the value of discharge corresponding to the 100-year flood), particularly if there isn’t a long record of observed data at a stream location. Learn more: The 100-Year Flood The 100-Year Flood--It's All About Chance
How are floods predicted?
Flood predictions require several types of data: The amount of rainfall occurring on a real-time basis. The rate of change in river stage on a real-time basis, which can help indicate the severity and immediacy of the threat. Knowledge about the type of storm producing the moisture, such as duration, intensity and areal extent, which can be valuable for determining possible severity of the...
How can I obtain river forecasts (flood forecasts)?
River forecasts (flood forecasts) are made by the National Weather Service River Forecast Centers and released through local Weather Service Offices. This NOAA website has a map showing the location of the forecast centers, their areas of responsibility, and by clicking into a region the location of the gages they use. The also provide a section for long-range river flood risk . The vast majority...
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