Ice dam risk in Poughkeepsie, NY
Ice dams in Poughkeepsie, NY: how often
21.2 dam days a winter
High risk. On an ordinary house in Poughkeepsie, conditions for an ice dam come on about 21.2 days in a normal winter, mostly in February and January.
Poughkeepsie averages 59 inches of snow a year and about 78 days with snow on the ground. Snow that lies that long is what turns a little attic heat into a ridge of ice at the eave. 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 Poughkeepsie
| Attic | Dam days | Risk |
|---|---|---|
| Air-sealed and well insulated | 12.2 | Moderate |
| Typical, some insulation, not air-sealed | 21.2 | High |
| Older or poorly insulated, warm attic | 32.6 | High |
Sealing and insulating a typical attic takes out about 9.0 days a winter here. It drops the risk from high to moderate. An older house with a warm attic should expect closer to 32.6 days.
Preventing ice dams on a Poughkeepsie 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.
- At the next reroof, ask for ice-and-water membrane under the shingles from the eave to at least 24 inches inside the wall line. It does not stop a dam; it stops the leak when one forms.
Which to spend on first: air sealing or heat cable.
Poughkeepsie winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 14.6 | 21.0 | 7.2 |
| February | 14.6 | 21.4 | 6.5 |
| March | 12.4 | 17.4 | 3.5 |
| April | 1.8 | 1.6 | 0.1 |
| October | 0.1 | 0.0 | 0.0 |
| November | 2.8 | 2.7 | 0.3 |
| December | 12.9 | 13.5 | 3.7 |
Poughkeepsie next to nearby towns
Poughkeepsie ranks 33 of 90 New York cities here for ice-dam days, behind Utica at 46.1 days.
- Beacon, NY 13 mi, 14.8 days
- Newburgh, NY 14 mi, 17.1 days
- Kingston, NY 17 mi, 21.2 days
- Woodbury, NY 27 mi, 14.8 days
- Kiryas Joel, NY 28 mi, 14.8 days
Where these numbers come from
NOAA 1991–2020 climate normals from Mohonk Lake, 13.2 miles from Poughkeepsie. 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.