
Onlookers walk through Old Fort Western admiring the swollen Kennebec River in Augusta on Dec. 20, 2023, after a storm caused extensive flooding in the city and many other communities. That storm and others have caused officials to reassess the flood warning system for Augusta, lowering the threshold for when the public and government officials are warned of rising water levels. Anna Chadwick/Morning Sentinel file
AUGUSTA — Flooding in 2023, including the Christmastime storm that breached the banks of the Kennebec River from Waterville to Gardiner, highlighted the need to update warning systems so that property owners and government officials aren’t caught by surprise.
In Augusta, where the 2023 “Grinch Storm” forced authorities to cut off power downtown due to safety concerns, that means the river levels that trigger various flood warnings — which are divided into action, minor, moderate and major — have been significantly lowered.
The water level at which flooding is deemed to be moderate is now 17 feet, down from 25 feet, and the major flooding level was dropped from 30 feet to 25 feet.
The updates were necessary to reflect changing conditions, officials said, including in the climate, which is a factor in the increasing number of large storms in the area.
Dave Groder, fire chief and emergency management leader for the city of Augusta, said the December 2023 storm “snuck up on us.” He and other officials worked with the National Oceanic and Atmospheric Administration, National Weather Service and other entities to review flood-level warnings.
“One hundred-year storms aren’t really 100-year storms anymore,” Groder said.
Sarah Jamison, senior hydrologist for the National Weather Service in Maine, who is overseeing the update to the flood warning system, said the hope is members of the public and responding agencies recognize the change in flood categories as signifying an increase in risk, and the need to make the proper preparations.
In Augusta’s case, that means the call for action to prepare and respond to rising water levels will come earlier, ideally providing more time to close off streets and parking lots, warn riverside property owners, move cars parked near the river, and tell residents to be aware.
During the December 2023 storm, the Kennebec River crested at 26.9 feet in Augusta, meaning now it’d be deemed a major storm, but it was then only categorized as moderate.
Groder said if the changes had been in place at the time of the storm, it likely would not have changed the city’s response. He and other public officials, including longtime Public Works Director Lesley Jones, are experienced river watchers, he said, and know what to expect as the water rises.
But, he said, the changes could be valuable to others, and prompt action by members of the public sooner.
Jamison agreed. “Honestly, the officials in Augusta are very attuned to the river and know how to respond based on the levels even without our designations,” she said. “However, anyone new to the community and unfamiliar with the Kennebec can use these thresholds to plan accordingly.”
Groder said there were so many factors in the December 2023 storm, he doesn’t think anyone could have predicted it.
Augusta City Councilor Eric Lind, a former Maine Air National Guard general, said the Kennebec River is huge, with numerous tributaries, and climate change is taking place, so it is not possible to predict all flooding that will occur.
“All we can do is take it seriously and never take our foot off the gas,” Lind said. “The river is scary and hard to predict. There are so many variables and it’s so much water, it could change in a heartbeat.”

The fast-moving and high waters of the Kennebec River flow under Calumet Bridge at Old Fort Western in downtown Augusta on March 7, 2024. Joe Phelan/Kennebec Journal file
The National Weather Service’s flood warning system uses stream gages operated by partners such as the U.S. Geological Service and dam operators to develop hydrologic models. Those models, Jamison said, use rainfall and snowmelt information to forecast river levels at those points on the river.
The warning program goes back nearly 100 years, with a growing number of forecast points improving accuracy.
While updates to the system were planned before the floods of 2023, Jamison said, those storms helped officials better understand the impacts that can happen in moderate flooding levels. She said the Weather Service routinely reassesses flood stages no less than every five years.
The update made no changes in Hallowell. The river gage was installed there in 2018, Jamison said, and flood stages were set then.
In Gardiner, there is no official National Weather Service forecast point. Jamison said modeling flooding there is made more difficult by the significant tidal influence, as well as the impact of Cobbossee Stream, which enters the Kennebec through downtown Gardiner.
She said the Weather Service plan to advance its hydrologic modeling to address communities like Gardiner in the future with water forecasting techniques is in development now.
The program sets flood levels on other rivers in Maine, not just the Kennebec. Jamison said they’re looking to make changes along the Saco River this year, and expand river forecasting services north of Skowhegan to The Forks.
Send questions/comments to the editors.
We invite you to add your comments. We encourage a thoughtful exchange of ideas and information on this website. By joining the conversation, you are agreeing to our commenting policy and terms of use. More information is found on our FAQs. You can modify your screen name here.
Comments are managed by our staff during regular business hours Monday through Friday as well as limited hours on Saturday and Sunday. Comments held for moderation outside of those hours may take longer to approve.
Join the Conversation
Please sign into your CentralMaine.com account to participate in conversations below. If you do not have an account, you can register or subscribe. Questions? Please see our FAQs.