With the threat of a land-falling hurricane always looming from June through October, the idea of a tropical storm doesn't carry the same weight. Sometimes we can even find ourselves 'seeing what else is on' after an approaching storm is downgraded from hurricane status on it's way toward New England. However, these systems themselves can pack their own punch, only slightly different from their more mature hurricane siblings. Part of the way in which we can understand their threat, is by examining the direct ways and specific places all tropical systems impact western Massachusetts the greatest.

Western Massachusetts Trouble Spots from Tropical Systems

"You don't need a hurricane to get a devastating condition." David Vallee says. David Vallee is the Hydrologist-in-charge of the Northeast River Forecast Center. Though high winds and storm surge are the most notorious aspects of a hurricane, inland flooding is actually the deadliest part of a tropical system. Not too many storms were able to push hurricane force winds up the Pioneer Valley, but again, as Vallee says, "it doesn't take a full fledged hurricane to dump a foot of rain." We don't have to worry about storm surge up here either, so it's really down to flooding rains outside of rarer hurricane winds, and perhaps tropical storms are more apt to get this accomplished. In the Summer of 2008, tropical storm Hanna came across New England, showing us a small picture of what such a system is like. Part of understanding why tropical storms are worrisome, comes with understand how and where hurricanes  themselves impact the most when headed to the area.

"The people most at risk, are the people living along the mainstem Connecticut River, and then anybody on the east-facing slopes of the Berkshires." The higher terrain will experience the higher gusts from a storm no matter what direction, but, as far as the rain is concerned, "that's where elevation helps to lift the air, wring out more moisture...You'll get higher rainfall in the higher terrain...and where does that rainfall end up...in the mainstem Connecticut River."

A 'watershed' describes a region of land in which all the precipitation that falls over that area would eventually drain into a specific river, even after flowing through smaller tributaries to get there. Sometimes, this is also referred to a 'Basin'. The Connecticut River basin encompasses the area from the peaks of the Berkshires to the Quabbin area of the Worcester Hills. Rainfall would flow from all these areas into smaller rivers (and their basins)...for example, the Westfield River, the Deerfield River, or the Chicopee River...and eventually empty their contents into the Connecticut River, itself only emptying into the Atlantic Ocean.

So Why Worry About Tropical Storms?

"You cannot kill a tropical core...You cannot kill the center of these tropical systems that quickly," David Vallee says, and it's one of the reasons why these storms can sometimes end up more remarkable than hurricane strikes-- because of their seeming surprise. Everyone braces for a hurricane impact, but not as many would follow along a weakened tropical system.

There are three kinds of arrivals these storms can make. One way would be a storm that forms over the Atlantic and makes landfall itself as only a tropical storm, perhaps only attaining tropical storm strength over its lifespan (Tropical Storm Carrie, 1972)...A storm could also have attained hurricane status, even major hurricane status, and then later impacted this area as a tropical storm, far from the location of initial land-fall (Hurricane Floyd, 1999). These first two categories, though often following through on an advertised warning, usually come with a fair amount of attention and calls for caution. A sub-category of the same, sometimes the New England area experiences tropical storm-force effects from an land-falling hurricane that is transitioning into an extratropical system, and frontal development within the system channels excess moisture and gusty winds to the region despite being far from the center (Hurricane Connie, 1955). The last category of tropical storms that impact the local area are of particular concern, because they almost always slide under the radar. These would be storms that attained tropical storm strength, made landfall far from the New England area, then was determined as tropically dissipated...yet still caused devastating rains characteristic of tropical storms anyway. "The remnants of Allison came across western Massachusetts in 2001," David Vallee retells. "She was a strong tropical storm when she hit the Texas coastline...Seven days later she made her way off the New Jersey shore...dumped a half-foot of rain...and laid down an F-1 tornado. That was a remnant of a former tropical storm...You've got to keep you're eye on every one of these things."

Hurricanes that strike New England are known for their forward speed (and therefore winds and surge)...but this fast forward speed also tends to limit the still copious amounts of rain they bring. Many of the top-ten 24-hour rainfall records along the Texas Coast, where tropical systems arrive at a paltry 10-12mph, are greater than 30"...but up in New England, hurricanes move in at an average of 30+ mph, never lingering around long enough to bring an amount like that even once. By contrast, for a variety of reasons, tropical storms typically happen to move more slowly near the New England area. Even though they aren't channeling the intensity of moisture content of a hurricane, they are able to display their wares for a considerably longer period of time. David Vallee uses perhaps the best example: "It was Connie and Diane that will probably remain as the greatest flood ever to strike the Connecticut River Valley. Two tropical systems-- Connie, remnant tropical rainfall of 4"-8", followed five days later by nearly 2-feet of rain from Diane...across all watersheds. Diane set the greatest single day rainfall record for New England: 18.15" in Westfield, MA. 18" of rain, from a 50mph Tropical Storm named Diane."