Ice dam risk in New Castle, PA
Ice dams in New Castle, PA: how often
11.5 dam days a winter
Moderate risk. On an ordinary house in New Castle, conditions for an ice dam come on about 11.5 days in a normal winter, mostly in January and February.
New Castle averages 28 inches of snow a year and about 42 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 New Castle
| Attic | Dam days | Risk |
|---|---|---|
| Air-sealed and well insulated | 6.9 | Moderate |
| Typical, some insulation, not air-sealed | 11.5 | Moderate |
| Older or poorly insulated, warm attic | 17.3 | High |
Sealing and insulating a typical attic takes out about 4.6 days a winter here. It does not move the risk band, but it shortens every dam. An older house with a warm attic should expect closer to 17.3 days.
Preventing ice dams on a New Castle 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 Castle winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 10.1 | 15.6 | 4.9 |
| February | 7.7 | 11.9 | 3.5 |
| March | 3.7 | 4.9 | 1.0 |
| April | 0.3 | 0.2 | 0.0 |
| November | 0.8 | 1.5 | 0.2 |
| December | 4.9 | 7.4 | 1.8 |
New Castle next to nearby towns
New Castle ranks 22 of 68 Pennsylvania cities here for ice-dam days, behind St. Marys at 26.9 days.
- Hermitage, PA 17 mi, 16.6 days
- Youngstown, OH 17 mi, 16.6 days
- Sharon, PA 18 mi, 16.6 days
- Niles, OH 25 mi, 9.1 days
- Butler, PA 25 mi, 15.3 days
Where these numbers come from
NOAA 1991–2020 climate normals from NEW Castle 1 N, 1.7 miles from New Castle. 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.