Preparedness in the Superstorm Era
Getting ready for Hurricane Lee and the new normal of more intense, unpredictable weather events
We’ve been watching Hurricane Lee carefully since last week, when the newly formed storm grew unusually and alarmingly fast from a Category 1 to a Category 5 hurricane within 24 hours. The threshold for what meteorologists call “rapid intensification” is when a storm speeds up by 35 mph over a 24-hour period. Lee gained 85 mph in a day—the third fastest intensification over all the years of satellite record-keeping, after Hurricane Felix in 2007 and Wilma in 2005. Warmer water fuels storm intensity because more evaporation and heat get into the air (Lee formed over Atlantic Ocean waters that are 3-4 degrees Fahrenheit hotter than average). Over the last five days, the storm has weakened, but the spread of its wind field has gotten larger.
The most current projections have Lee passing by the Massachusetts coastline early Saturday morning through the afternoon, before making landfall Saturday evening or early Sunday near the tip of Maine, New Brunswick, and Nova Scotia. Lee has weakened to a Category 1 Hurricane at the moment, with 100 mph winds near Bermuda this morning, and will continue weakening as it moves north. All of Suffolk County is currently under a Tropical Storm Watch.
Although the storm has been turning east and farther away from the coast as it comes closer, its radius is so wide that rain and wind will reach farther inland and impact Boston. We expect Saturday to feel like a Nor’easter with rain and winds up to 30 mph. The City of Boston’s Emergency Management department has a list of suggested preparations for residents to be ready for any potential tropical storm or hurricane: secure any loose outdoor furniture or rain gutters or downspouts, have flashlights with batteries ready in case of power outages, charge your phone or any electronic medical devices, try to plan ahead to be able to stay indoors during the storm, and check on your friends and neighbors. To get the latest emergency alerts from the city by email or text message, sign up for AlertBoston here.
We are taking every step to prepare for the unexpected this Saturday, and everyday—as storms are becoming more intense, more frequently. Our administration has been steadily growing our emergency management and preparedness efforts over the last year to go beyond the usual protocols for fire or water main breaks. Climate-related emergencies such as heat waves, dangerously strong winds, and flooding from coastal storm surge or intense rainfall is more and more our new reality.
In New England, flooding is one of the biggest threats to our physical infrastructure. Two days ago, Governor Healey declared a state of emergency after our neighbors 50 miles to the west of Boston in Leominster received 9.5 inches of rain over 5-6 hours, causing extreme flash flooding that overwhelmed that region. That same day, Providence firefighters rescued 25 people trapped after intense flash floods devastated a shopping center. Two months ago, days of rain in Vermont caught residents by surprise, damaging more than 4,000 homes and 800 businesses.
Cities along the coast are at greater risk. Boston has had more high tide flooding days than any other city in the country, and the frequency of high tide flooding has accelerated by more than three times the national average. Even under blue skies with no rain or wind, low-lying parts of our city are regularly experiencing this “sunny day flooding.”
So how can we keep residents safe during these more frequent and more intense weather events? First we have to understand how to translate storm projections into flooding preparations:
Water & Sewer Infrastructure capacity: Every city’s water and sewer system is designed to absorb a certain amount of water based on average rainfall conditions for that geographic area. In Boston, our system is built to absorb five inches of rain over a 24-hour period. The way to expand system capacity within the infrastructure itself is to replace existing pipes with bigger ones, which in an older city like Boston would be not only extremely costly, but impossible in many areas given space constraints.
Rainfall rate and amount: Being able to hold five inches of water over 24 hours is different from absorbing five inches of rain that come down quickly within an hour. Anything more than one inch per hour will start to raise concerns for flooding in Boston, so we look at the total inches of rain expected (based on how many hours the storm will linger) and the rate at which the rain will come down.
Storm surge: The wind speeds and direction in each storm determine the surge or additional sea level height that will be generated, on top of tide levels. Lee is projected to bring 1-4 feet of storm surge, but thankfully should arrive closer to low tide.
Tide times: Boston Harbor sees around a ten-foot tidal difference every six hours between high tide and low tide. A storm that peaks at high tide is far more dangerous than the same storm closer to low tide.
Geography and topography: Intuitively, homes that are at the bottom of a hill will experience more flooding than those at the top of the hill as the water runs down, and even more inland areas can be within a floodplain depending on elevation, proximity to rivers or streams, and more. The Boston Water and Sewer Commission built a storm viewer tool to understand how different storm scenarios impact different neighborhoods with coastal flooding.
Recent precipitation: When the ground and infrastructure are already saturated from recent heavy rains, there’s less capacity to efficiently absorb more water. This summer has been the second rainiest summer in Boston’s recorded history, following last year’s drought conditions. Hotter temperatures feed these extreme swings.
Other timing considerations: It was a relief that Lee will impact us on Saturday, when school isn’t in session and more people are able to stay indoors than during the workweek. Day of the week and time of day are entirely a matter of luck, but it can greatly affect how we prepare.
We carefully track all of the above, along with recording historical flooding information so we know exactly which buildings and streets have experienced flooding in the past. The biggest tool we have to address flooding is investing in resilience. We can build sea walls or raise the elevation of critical infrastructure such as roadways to block the water or minimize the impact of flooding. And we can find ways to divert or absorb water through green infrastructure like trees, green roofs and rain gardens, permeable pavement, rain barrels—which hold water and slow it down from entering our water and sewer infrastructure, reducing the strain on our pipes.
Boston has set new standards for roadway projects and other public developments to include green infrastructure as the default, and we are working on ways to align stormwater costs with the benefits of having green infrastructure on private property as well.
Even as we look to fight climate change and improve our resilience, we must be prepared for disaster relief after the big weather emergencies we know we’ll face. Last year, the Boston Fire Department acquired two emergency vehicles designed for high water or wildfire, and now their teams are trained for water rescue and equipped with flotation suits. For this upcoming storm, these high-water vehicles will be stationed in the areas with greatest anticipated flooding, and we will have marine units in the harbor, and a boat on the Charles River for any necessary operations. We also have plans for a neighborhood shelter system if a storm rises to a certain threshold, which thankfully Lee does not, and additional services for residents with disabilities and residents experiencing homelessness.
But as more and more communities experience flash flooding and unexpected climate events, preparedness means not only having government plans in place, but also community engagement long before the disaster so residents are set with supply kits, knowledge of evacuation plans, and multiple methods of communication to receive the latest alerts. Our Emergency Management department coordinates first responders and city agencies to hold regular community outreach events to build connections and share information hopefully long before the need for disaster relief.
Preparedness requires an all-of-government and whole community effort. As we continue to build out our planning and engagement efforts, I’ll share more updates on heat resilience, winter storms, and more.
Stay safe and dry on Saturday, and once again please take a look at our preparedness checklist!
Did I miss your apology for alarming the public over a non event, Mayor Wu?
Thanks. Great summary of the risks and preparation for a weather event with all the attendant uncertainties of recent storms fueled by a warming world.