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.
The U.S. Geological Survey (USGS) New England Water Science Center, in cooperation with the Federal Emergency Management Agency (FEMA), is conducting a study to characterize the magnitude and extent of the December 18-21, 2023 Flood in various portions of the State of Maine.
Catastrophic flooding occurred in the State of Maine on December 18-21, 2023. A slow-moving rainstorm accompanied by 50-60 mph winds and high dewpoints resulted in 4 to 8 inches of rainfall (48-hour total) and an average snowmelt of 1.5 to 2.5 inches. In mountainous terrain additional snowmelt was reported, with an average total of 3.5 to 4.5 inches. The high amount of rainfall, snowmelt, and runoff caused multiple rivers and tributaries to peak at record levels, in some cases exceeding previous records set by the historic flood of April 1987.
To understand the magnitude and extent of the flood, the U.S. Geological Survey (USGS), in cooperation with the Federal Emergency Management Agency (FEMA), is documenting and analyzing flood characteristics. This includes documenting and analyzing the maximum elevation of the flood through high-water marks (HWMs), which may be used to verify streamflow measurements and put the flood in historical context. The elevations will be compared to those documented from the April 1987 flood. Probability of the flood will additionally be computed and reported as Annual Exceedance Probability and Recurrence Intervals. These data combined may then be used to validate the accuracy of current effective flood insurance studies. Additionally, due to the flood’s occurrence during early winter when reservoir storage levels are high, analysis of the storage prior to and during the event will be done to evaluate how this may have affected the intensity of the flood.
This information is critical for recovery efforts and planning purposes to help minimize losses in future floods and will be available through a USGS Scientific Report and a USGS Data Release. HWM data will be uploaded to the USGS Flood Event Viewer and included in a user-friendly interactive dashboard that compares the December 18-21, 2023 Flood and the April 1987 Flood HWMs. An additional dashboard will contain flood frequencies of the event at USGS streamgages. To learn more about the USGS’s work on the December 18-21, 2023 Flood see the Maine Flood Presentation above.
New England Flood Information
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 USGS hydrologist records a high-water mark on a tree near the Crooked River in Waterford, Maine in the days following a significant flood event.
A USGS hydrologist records a high-water mark on a tree near the Crooked River in Waterford, Maine in the days following a significant flood event.
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.

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.

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.
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
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
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.
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.
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.
The U.S. Geological Survey (USGS) New England Water Science Center, in cooperation with the Federal Emergency Management Agency (FEMA), is conducting a study to characterize the magnitude and extent of the December 18-21, 2023 Flood in various portions of the State of Maine.
Catastrophic flooding occurred in the State of Maine on December 18-21, 2023. A slow-moving rainstorm accompanied by 50-60 mph winds and high dewpoints resulted in 4 to 8 inches of rainfall (48-hour total) and an average snowmelt of 1.5 to 2.5 inches. In mountainous terrain additional snowmelt was reported, with an average total of 3.5 to 4.5 inches. The high amount of rainfall, snowmelt, and runoff caused multiple rivers and tributaries to peak at record levels, in some cases exceeding previous records set by the historic flood of April 1987.
To understand the magnitude and extent of the flood, the U.S. Geological Survey (USGS), in cooperation with the Federal Emergency Management Agency (FEMA), is documenting and analyzing flood characteristics. This includes documenting and analyzing the maximum elevation of the flood through high-water marks (HWMs), which may be used to verify streamflow measurements and put the flood in historical context. The elevations will be compared to those documented from the April 1987 flood. Probability of the flood will additionally be computed and reported as Annual Exceedance Probability and Recurrence Intervals. These data combined may then be used to validate the accuracy of current effective flood insurance studies. Additionally, due to the flood’s occurrence during early winter when reservoir storage levels are high, analysis of the storage prior to and during the event will be done to evaluate how this may have affected the intensity of the flood.
This information is critical for recovery efforts and planning purposes to help minimize losses in future floods and will be available through a USGS Scientific Report and a USGS Data Release. HWM data will be uploaded to the USGS Flood Event Viewer and included in a user-friendly interactive dashboard that compares the December 18-21, 2023 Flood and the April 1987 Flood HWMs. An additional dashboard will contain flood frequencies of the event at USGS streamgages. To learn more about the USGS’s work on the December 18-21, 2023 Flood see the Maine Flood Presentation above.
New England Flood Information
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.
A USGS hydrologist records a high-water mark on a tree near the Crooked River in Waterford, Maine in the days following a significant flood event.
A USGS hydrologist records a high-water mark on a tree near the Crooked River in Waterford, Maine in the days following a significant flood event.
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.

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.

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.
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
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
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.
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.
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.