The July 2023 Northeastern United States floods caused historic, devastating floods across the U.S. state of Vermont, primarily on July 9 and 10. In preparation for the floods, the Weather Prediction Center had issued its first-ever high risk for excessive rainfall for areas in the National Weather Service in Burlington, Vermont's coverage zone, while state governor Phil Scott declared a state of emergency. The flooding and damage stemming from it was described by Scott as "historic and catastrophic", as much of the state received more than of rainfall. Additionally, already-saturated ground across Vermont and other meteorological factors, including sufficient moisture and high dewpoints and precipitable water values, contributed to the severity of the floods.
The most impacted areas of the state as a result of the flooding included the capital city of Montpelier, the city of Barre, and the towns of Londonderry, Ludlow, and Weston. The highest rainfall total was recorded in Calais, Washington County; of rain fell there. The floods also caused two fatalities and widespread damage to infrastructure and communities across the state, including in and around of the Appalachian Mountains. While conducting recovery operations in response to the event, state officials stated that the flooding and its damages was "bigger than Hurricane Irene", a Category 3 hurricane which also caused damaging floods across Vermont and the Northeastern United States in 2011. The floods were also compared to other historic flood events that occurred in the state's past, including Irene and the Great Vermont Flood of 1927.
Background Vermont had been subject to other notable weather events and phenomena in 2023, including a stretch of above-average temperatures and drought conditions that was present across the Northeastern United States for most of the year and smoke emitted from wildfires in Canada. The state also had previously suffered catastrophic flooding events in the last century, including in 2011 stemming from a weakening Hurricane Irene and the Great Vermont Flood of 1927. Flooding events have been destructive due in part of the mountainous, rugged terrain that encompasses much of the state, including the Appalachian Mountains. The government of Vermont implemented a state hazard mitigation plan in 2018, which failed nearly six years later as a result of disaster declarations from natural disasters including the 2023 flood where the plan's tasks had not been implanted during recovery efforts. After the floods in 2011, the state's government started a reconstruction effort costing $130 million to rebuild homes and structures damaged by the disaster event. This involved the purchase of nearly 150 homes during reconstruction efforts; these were built in areas where rivers nearby had the potential to overflow and inundate them, however. A 728-page state document published in 2015 also noted the damages sustained from Irene and outlined projects necessary for communities to be protected from future floods; this was not successfully complete due to financial reasons, however. Despite flooding being the primary natural disaster in the state, much of Vermont had not been included in the Federal Emergency Management Agency (FEMA)'s flood-tracking system for potential development of structures that were not subject to the threat of future floods. The chances of two significant flood events impacting the state in a short period of time were at, according to The Washington Post, .6%. The floods also occurred amid a global warming crisis and an El Niño event; these were some of the contributing factors to the flood event itself. A study conducted by Dartmouth College showed that, with the rate of climate change occurring, extreme weather events across the Northeast was to increase 52% by 2100.
Meteorological synopsis
On July 9, sufficient moisture was noted across much of the Northeastern United States as high dewpoints and precipitable water values (PWATs) ranged around , which resulted in heavier rainfall amounts and rates as convection moved in from the southwest. This atmospheric setup was primarily caused by a jet stream located directly over New England that pulled in moisture from the south, which was wedged in between a low-pressure area over Canada near the Upper Peninsula of Michigan and a high-pressure area located in the northern Atlantic Ocean, the latter of which was a large, expanded area off the coast of Nova Scotia towards Greenland. The moisture was also likely contributed from the warm waters of the Atlantic Ocean as well, evaporating and producing heavy rainfall across the Northeast. Additionally, a trough had progressed from the Great Lakes and the Ohio River regions to portions of Vermont and New York, where it slowed down in movement after reaching the latter areas; this caused extended, prolonged heavy rainfall to northeastern New York and Vermont.
An area of convergence also influenced additional development of showers and thunderstorms across much of the state. Some areas impacted were already saturated by previous rainfall that occurred two days prior, where localized areas had already received with isolated higher amounts. The aforementioned atmospheric trend continued into July 10, which extended the period of heavy rainfall across the same areas that were impacted the day before. The floods was described by atmospheric and environmental research scientists as "extremely unusual" and linked to effects stemming from climate change. There were also instances of wind damage as the convection also downed several trees and branches amid a level 1/marginal risk being issued for severe weather by the Storm Prediction Center for much of New England. Most parts of the state received of rainfall, with occurring across the Green Mountains and nearby areas with localized higher amounts.
Additional heavy rains on July 16 resulted in the exacerbation of the already-saturated ground across much of the state, but was less significant than the event on July 9–10.
Preparations and impact On July 9, the Weather Prediction Center issued their first-ever high risk for flash flooding in the NWS Burlington coverage zone. Because of this, a state of emergency was declared by state governor Phil Scott, which allowed the use of out-of-state resources for emergency responders in the state.
Governor Scott described the widespread flooding in the state "historic and catastrophic" and "Irene 4.0", while state officials stated that the damages stemming from the floods and the flooding itself were more significant than Hurricane Irene, a Category 3 hurricane which caused widespread flooding impacts to the state in 2011. Scott's home itself was impacted by the floods as nearby roads near there were completely impassable as a result, which forced him to hike through snowmobile trails. The flooding prompted thirteen emergency management teams to rescue more than 100 people across Vermont. Initially, 4,087 homes and 839 businesses were reportedly damaged, with 754 of the damaged homes being uninhabitable and 314 people displaced as a result of the floods; however, more than 3,160 homes were eligible for damage repair assistance by the Federal Emergency Management Agency (FEMA) and the number of damaged businesses across the state was below 800 in a WCAX-TV total. According to applications submitted to FEMA, more than 2,900 homes were recorded to have been damaged, including 530 significantly and 14 destroyed. Peter Banacos, a meteorologist associated with the National Weather Service in Burlington, Vermont, compared the floods with the effects of Hurricane Irene in 2011 and noted that damage from the floods "exceeded" the latter event, with the Great Vermont Flood of 1927 only causing further damage than the two events. The United States Geological Survey also reported that some river levels caused by the heavy rainfall crested at record levels, breaking those set by Irene. During the event and its recovery process, all statewide swift boat rescue teams were activated. The damage caused by the severe weather and floods totaled in excess of $600 million (2023 USD).
Washington County
The county seat, Montpelier, was severely impacted by the floods. A travel ban was initiated after floodwaters inundated roads across the downtown area; the floodwaters itself also prompted a boil water notice issued for the entire city amid warnings that the city's drinking water system could potentially be contaminated as a result. Several of the city's government buildings, including Montpelier City Hall, were flooded and some were forced to relocate. Additionally, numerous businesses and homes were destroyed after flooding left them uninhabitable and unable to operate; this included a United States Postal Service building in the city's downtown area which did not open until 15 months later. Residents in the city were also forced to evacuate low-lying areas and locations near the Winooski River, after it crested to record flood levels not observed since Hurricane Irene; this included portions of downtown Montpelier. This also led to rising water levels at the Wrightsville Dam, which threatened to burst or overflow on July 11; it then receded by the evening hours of the day. At the Edward F. Knapp State Airport near Montpelier, of rain fell, setting a record for the heaviest rainfall in a single day in the city and breaking the previous record of set in 2011 by Hurricane Irene's remnants. Overall, nearly 140 businesses across the city were damaged, which resulted in damages in excess of $20 million; almost a dozen homes also sustained "severe" damage.
Nearby, the city of Barre also experienced similar impacts; there and Ludlow, a town in Essex County, were considered to be the most affected in terms of flash flooding. Rainfall totals in excess of there caused the Winooski River to overflow its banks and produced widespread flooding across the city, including the downtown area, where officials closed off until the floods receded. The combination of debris and several feet-deep mud caused by the floods induced odors across northern and downtown portions of the city. Additionally, several roads there, including Vermont Route 62, were flooded, damaged, or washed out completely; this forced officials to close them off. A 63-year-old man drowned in the flood-inundated basement of his home in Barre. The Thunder Road International SpeedBowl was scheduled to host the second event of the 2023 Superstar Racing Experience auto racing season on July 20, but the event was cancelled as result of the floods in the city. There were nearly 350 structures or properties damaged significantly; an additional 600 claims of damage were reported in Barre. The city also had 10 percent of its homes either destroyed or left uninhabitable.