Ice dam risk in New Bedford, MA
Will your roof get ice dams in New Bedford, MA?
6.8 dam days a winter
Moderate risk. On an ordinary house in New Bedford, conditions for an ice dam come on about 6.8 days in a normal winter, mostly in January and February.
New Bedford averages 33 inches of snow a year and about 28 days with snow on the ground. Plenty falls, but it tends to melt off between storms, which keeps the count lower than the snowfall suggests. That gap is why snowfall alone misleads.
What your attic does to that number in New Bedford
| Attic | Dam days | Risk |
|---|---|---|
| Air-sealed and well insulated | 4.5 | Low |
| Typical, some insulation, not air-sealed | 6.8 | Moderate |
| Older or poorly insulated, warm attic | 9.7 | Moderate |
Sealing and insulating a typical attic takes out about 2.3 days a winter here. It drops the risk from moderate to low.
Preventing ice dams on a New Bedford roof
- Air-seal the attic floor: the gaps around the hatch, light fixtures, plumbing stacks and the top plates of interior walls. This is the fix that removes the cause, and it usually costs less than a season of contractor ice removal.
- Rake the bottom three or four feet of roof after any storm that leaves more than about six inches, from the ground with a roof rake.
Which to spend on first: air sealing or heat cable.
New Bedford winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 10.9 | 10.0 | 2.7 |
| February | 8.5 | 9.3 | 2.4 |
| March | 6.6 | 4.9 | 0.9 |
| April | 1.7 | 0.2 | 0.0 |
| November | 0.4 | 0.1 | 0.0 |
| December | 4.4 | 3.9 | 0.8 |
New Bedford next to nearby towns
New Bedford ranks 57 of 58 Massachusetts cities here for ice-dam days, behind Pittsfield at 31.3 days.
- Fall River, MA 9 mi, 7.2 days
- Taunton, MA 19 mi, 8.2 days
- Bridgewater Town, MA 22 mi, 7.6 days
- Newport, RI 23 mi, 6.3 days
- East Providence, RI 24 mi, 6.0 days
Where these numbers come from
NOAA 1991–2020 climate normals from NEW Bedford Coop, 4.9 miles from New Bedford. A dam day is a day with snow on the roof and freezing at the eave while heat or sun melts the snow above it. This describes a normal winter, not this one.
- Snow-on-the-ground counts come from a second, nearby station, because the closest one does not record them.