Ice dam risk in Hammonton, NJ
Will your roof get ice dams in Hammonton, NJ?
3.6 dam days a winter
Low risk. On an ordinary house in Hammonton, conditions for an ice dam come on about 3.6 days in a normal winter, mostly in February and January.
Hammonton averages 24 inches of snow a year and about 17 days with snow on the ground. Most of it comes and goes within a few days. The conditions that make a dam need all three at once: snow, cold at the eave and heat above it.
What your attic does to that number in Hammonton
| Attic | Dam days | Risk |
|---|---|---|
| Air-sealed and well insulated | 2.9 | Low |
| Typical, some insulation, not air-sealed | 3.6 | Low |
| Older or poorly insulated, warm attic | 4.5 | Low |
The attic matters less in Hammonton than in colder towns: there are only 0.7 days a winter between a typical attic and a sealed one.
Preventing ice dams on a Hammonton roof
- Check the gutters before the first snow and clear them, so meltwater has somewhere to go. If you see icicles thicker than a finger along the eave after a storm, that is the early sign to look at the attic.
Snowy places are not always the worst: why snowfall misleads.
Hammonton winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 6.0 | 5.6 | 1.4 |
| February | 8.9 | 6.2 | 1.4 |
| March | 3.9 | 2.2 | 0.3 |
| April | 0.5 | 0.1 | 0.0 |
| November | 0.3 | 0.1 | 0.0 |
| December | 3.9 | 2.9 | 0.5 |
Hammonton next to nearby towns
Hammonton ranks 97 of 116 New Jersey cities here for ice-dam days, behind Hopatcong at 14.7 days.
- Pine Hill, NJ 14 mi, 3.6 days
- Lindenwold, NJ 16 mi, 3.6 days
- Vineland, NJ 18 mi, 3.4 days
- Glassboro, NJ 19 mi, 3.2 days
- Haddonfield, NJ 22 mi, 2.3 days
Where these numbers come from
NOAA 1991–2020 climate normals from Indian Mills 2 W, 9.6 miles from Hammonton. 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.