Powerful 'Microburst' Rainstorms Create Rising Tide Of Concern

By: Ed Maroney

Looking like the amphibious Amphicar of the 1960s, a vehicle sails through the parking lot at Stop and Shop after an August microburst.

ED MARONEY PHOTO

ORLEANS With much attention on the waves seeking to break through the dune protecting the parking lot at Nauset Beach, another watery battleground has been less prominent. But miles from its shorelines, the town is dealing with sudden torrential downpours well beyond flood zones, where the damages aren't covered by flood insurance.

The Aug. 9 microburst that hit the Lower Cape hard dropped as much as seven inches of rain in four hours, DPW/Natural Resources Director Tom Daley told selectmen Oct. 3. “A 100-year storm is seven inches in 24 hours,” he said. “Do the math and think of the intensity of that rainfall. Stormwater systems aren't designed for that. They never have been and most likely never will. Instead of a 12-inch pipe, you'd need a 36-inch pipe diameter all over town (at a cost of) millions of dollars.”

In 2017, Daley noted, the town was hit with seven inches of rain over 12 hours. Lydia DuPertuis, who lives in a condo complex on Old Colony Way, remembers that day well.

“We have a retention pond that abuts the property,” she said. “That pond completely overflowed into the parking lot...One of our neighbors put a canoe out there and gave kids a ride.” Seventeen units took in water, some up to basement ceilings.

“We had three dumpster loads taken out of the basements,” DuPertuis said. “A lot of belongings, a lot of books.” A couple of cars in the parking lot were a total loss as well. The condo association chipped in to rent the dumpsters and to cover a couple of pump-outs, but owners were on the hook for remediation of the damage to their units.

At the selectmen's meeting, Daley showed slides of the inundated intersection of Kettle Pond Way and Nickerson Road after August's storm. The highway garage at Bay Ridge Road took in water, he said, and “Eldredge Field was a lake.”

In an interview, Fire Chief Tony Pike said calls for service soared to between 60 and 70 that day in August, well over the summer average of 40. People called about flooded basements, wires down, transponders blown, vehicle crashes and two serious structure fires.

“I think people are starting to be well aware of the hazards with these microburst storms,” Pike said. “These smaller incidents are becoming ominous really fast without warning. It's extremely concerning to me.”

The Massachusetts Homeowners Handbook to Prepare for Coastal Hazards (available for download at seagrant.mit.edu/publications/MITSG_13-10.pdf) lists as “Myth No. 3” the notion that “I don't live near the coast, so I am safe.” The handbook notes that “the vast majority of damage or destruction” from events such as Hurricane Irene in 2011 “was caused by inland flooding associated with extreme rainfall.” And get ready for more.

“Precipitation extremes appear to be increasing, as evidenced by an increase in heavy downpours,” the handbook reports. “Less winter precipitation is falling as snow and more as rain...During heavy rain events, not only will some roads be impassable due to flooding, but after waters recede, more roads and culverts may need repairs.”

After showing selectmen slides taken during the August storm, Daley said, “The point is, we can't fix all of these. We're gonna do our best (with) berms and improved drainage.” Selectman Kevin Galligan said that many residences have their own stormwater drainage systems that need to be maintained, and Daley added that Orleans “has a bylaw that says you've got to keep your drainage on your property. It's more than most towns have.”

The town is crafting an update to its hazard mitigation plan under the direction of Director of Planning and Community Development George Meservey. The work is being done as part of a Municipal Vulnerability Assessment, for which the town received a $30,000 grant. “An array of potential hazards will be evaluated,” Meservey wrote in an email, “including significant short rain events such as the one that occurred in August with 4-7 inches of rain in a morning. The plan was last updated in 2004.”

Planning is also going on at Lydia DuPertuis's condo complex. “We're looking at this (flooding) from an engineering point of view,” she said. “Obviously, we're going to have to do something.” One happy result of their troubles is that “we really came together as a community in terms of helping each other out. That's always a good thing.”

“Everybody that lives in a coastal town should be in the readiness business for themselves, to prepare their homes for issues like this,” Pike said. “Make sure you have flashlights and your medications. (And) one problem with severe storms is way more people out driving the roads than should be. There are more than several vehicle crashes because visibility is down to zero. Shelter in place unless you need to be evacuated.”

Call us and we will come is Pike's message to citizens – but please don't call the department's business line. “You have to call 911 for any emergency, big or small,” the chief said. “The only reason to use the business line at the fire station is for business; 911 is able to stack calls accordingly for us to respond to. During a storm, 911 is the most appropriate way.”