Vermont, a landlocked state in the northeastern United States, does not experience a hurricane in the traditional sense of a Category 1 through 5 storm. Geographic reality prevents tropical cyclones from maintaining full hurricane strength as they travel hundreds of miles inland. What Vermont does encounter are the weakened but still powerful remnants of these storms, which bring a distinct set of weather hazards.
Defining the Storm Categories
The classification of tropical systems is based entirely on wind speed, which dictates the official designation a storm carries. A tropical cyclone begins as a tropical depression, featuring a defined circulation and maximum sustained winds of 38 miles per hour (mph) or less. Once winds increase to between 39 and 73 mph, the system is upgraded to a tropical storm.
A system officially becomes a hurricane when its maximum sustained winds reach 74 mph, categorized on the Saffir-Simpson Hurricane Wind Scale (SSHWS). This scale rates storms from Category 1 (74–95 mph) to Category 5 (157 mph or higher). The SSHWS measures a storm’s destructive wind potential, but it does not account for the massive amount of rainfall or the resulting inland flooding, which are often the greatest threats far from the coast.
Geographic Shielding and Storm Degradation
The distance from the Atlantic Ocean and Gulf of Mexico provides Vermont with a substantial defense against hurricane-force winds. Tropical cyclones draw their power from the heat and moisture of warm ocean water, which acts as their continuous fuel source. Once a storm makes landfall, this supply is immediately cut off, initiating rapid degradation.
As the storm moves inland, it encounters increased friction from terrain, forests, and buildings, which slows and disrupts the wind field. The storm also pulls in cooler, drier air from the continent, which cannot sustain the warm, moist core necessary for hurricane intensity. The Appalachian Mountains act as a physical barrier, further disrupting the storm’s structure. By the time a tropical system reaches Vermont, its wind speeds have almost always dropped below the 74 mph threshold, reclassifying it as a tropical storm or a post-tropical remnant.
The Actual Threat: Rain and Inland Flooding
While the wind hazard significantly diminishes, the vast amount of moisture gathered over the ocean remains trapped within the storm system, posing the primary danger to Vermont. A tropical remnant can carry rainfall rates far exceeding typical summer thunderstorms, often resulting in heavy, sustained precipitation over a short period. This is especially true when a storm interacts with the state’s mountainous terrain, which forces the moisture-laden air to rise and cool, dramatically increasing the rate of condensation and rainfall.
The state’s steep slopes and narrow river valleys are particularly vulnerable to this influx of water. Rain runs off the mountainsides with tremendous speed, turning small brooks and streams into raging torrents. This rapid runoff triggers flash flooding, the most dangerous hazard, capable of washing out roads, collapsing bridges, and carrying large debris. Saturated ground increases the likelihood of landslides and slope failures, adding to the destructive power of the floodwaters. The sheer volume of water can also cause major rivers, such as the Winooski and White Rivers, to crest well above flood stage, inundating populated areas built in historic floodplains.
Notable Historical Impacts
The most devastating example of a tropical remnant’s impact on Vermont was Tropical Storm Irene in August 2011. Although downgraded from a hurricane, Irene stalled over the state and delivered a staggering amount of rain, with some areas receiving up to eight inches of precipitation in less than 24 hours. The resulting floodwaters destroyed or severely damaged over 500 miles of state roads and roughly 200 bridges, isolating at least a dozen towns.
The destruction caused by Irene was a consequence of water, not wind, demonstrating the disproportionate inland threat of tropical remnants. More recently, the remnants of Hurricane Beryl in July 2024 brought a similar deluge, with some regions receiving up to six inches of rain, triggering flash floods that collapsed roads and damaged infrastructure. These events confirm that while Vermont is shielded from the coastal wind damage of a full hurricane, the hydrological hazard posed by the storm’s residual moisture is a recurring reality.