Ice dam risk in Oneonta, NY
How often ice dams form in Oneonta
28.1 dam days a winter
High risk. On an ordinary house in Oneonta, conditions for an ice dam come on about 28.1 days in a normal winter, mostly in January and February.
Oneonta averages 83 inches of snow a year and about 86 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 Oneonta
| Attic | Dam days | Risk |
|---|---|---|
| Air-sealed and well insulated | 14.0 | Moderate |
| Typical, some insulation, not air-sealed | 28.1 | High |
| Older or poorly insulated, warm attic | 45.8 | Severe |
Sealing and insulating a typical attic takes out about 14.2 days a winter here. It drops the risk from high to moderate. An older house with a warm attic should expect closer to 45.8 days.
Preventing ice dams on a Oneonta 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.
Oneonta winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 20.7 | 23.3 | 8.8 |
| February | 19.5 | 22.3 | 8.1 |
| March | 14.5 | 16.6 | 4.6 |
| April | 3.3 | 2.1 | 0.3 |
| May | 0.3 | 0.1 | 0.0 |
| October | 0.8 | 0.3 | 0.0 |
| November | 6.3 | 5.0 | 1.0 |
| December | 17.6 | 16.1 | 5.3 |
Oneonta next to nearby towns
Oneonta ranks 4 of 90 New York cities here for ice-dam days, behind Utica at 46.1 days.
- Utica, NY 45 mi, 46.1 days
- Binghamton, NY 50 mi, 26.0 days
- Johnson City, NY 51 mi, 26.0 days
- Oneida, NY 53 mi, 27.3 days
- Gloversville, NY 55 mi, 24.7 days
Where these numbers come from
NOAA 1991–2020 climate normals from Emmons, 3.0 miles from Oneonta. 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.