Ice dam risk in Olean, NY
Will your roof get ice dams in Olean, NY?
22.7 dam days a winter
High risk. On an ordinary house in Olean, conditions for an ice dam come on about 22.7 days in a normal winter, mostly in January and February.
Olean averages 65 inches of snow a year and about 74 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 Olean
| Attic | Dam days | Risk |
|---|---|---|
| Air-sealed and well insulated | 12.0 | Moderate |
| Typical, some insulation, not air-sealed | 22.7 | High |
| Older or poorly insulated, warm attic | 36.2 | Severe |
Sealing and insulating a typical attic takes out about 10.8 days a winter here. It drops the risk from high to moderate. An older house with a warm attic should expect closer to 36.2 days.
What to do about ice dams in Olean
- 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.
Olean winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 17.6 | 21.4 | 7.9 |
| February | 13.7 | 18.7 | 6.3 |
| March | 10.1 | 12.2 | 3.1 |
| April | 1.8 | 1.5 | 0.2 |
| October | 0.3 | 0.3 | 0.0 |
| November | 6.3 | 5.2 | 1.1 |
| December | 14.9 | 15.0 | 4.2 |
Olean next to nearby towns
Olean ranks 26 of 90 New York cities here for ice-dam days, behind Utica at 46.1 days.
- Jamestown, NY 41 mi, 25.4 days
- St. Marys, PA 44 mi, 26.9 days
- Dunkirk, NY 53 mi, 25.0 days
- Lackawanna, NY 55 mi, 21.2 days
- Lancaster, NY 58 mi, 21.2 days
Where these numbers come from
NOAA 1991–2020 climate normals from Olean, 1.1 miles from Olean. 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.