Areas of Massachusetts and Rhode Island received 10 inches of rain within 6 hours on Tuesday, causing major flooding and triggering emergency declarations, boat rescues and evacuations due to aging dam structures.
In Leominster, north of Boston, schools closed and shelters opened. Mayor Dean Mazzarella said most buildings in the downtown area were flooded and some had collapsed.
About 300 people were evacuated, some of whom were living near one of the city’s nearest earthen dams, which is listed in poor condition and subject to replacement.
According to planning documents, the city experiences floods from time to time. The North Nashua River saw significant high flow events in 1936, 1938, and 1955.
According to a planning document, “During this flood, roads were submerged, dams broke and bridges collapsed.”
Additional rainfall is expected in the area on Wednesday, and parts of the state may experience flooding as Hurricane Lee approaches over the weekend.
Officials said the rain was a 200-year event, meaning that in any given year, there is a 1 in 200 chance of this much rainfall occurring in a single event.
Climate change is expected to lead to more frequent and more intense rainfall events. Experts said the signature was already present in this week’s floods, where moisture in warm, humid air contributed to the rain.
“It’s going to get worse as long as fossil fuel emissions continue,” said Matthew Barlow, a climate scientist at the University of Massachusetts-Lowell. “So this will not be a new normal. Unless we choose to dramatically reduce emissions, this will be a path on the way to even more intensive systems.”