Ice dam risk in State College, PA
Ice dams in State College, PA: how often
12.5 dam days a winter
Moderate risk. On an ordinary house in State College, conditions for an ice dam come on about 12.5 days in a normal winter, mostly in February and January.
State College averages 44 inches of snow a year and about 46 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 State College
| Attic | Dam days | Risk |
|---|---|---|
| Air-sealed and well insulated | 7.1 | Moderate |
| Typical, some insulation, not air-sealed | 12.5 | Moderate |
| Older or poorly insulated, warm attic | 19.2 | High |
Sealing and insulating a typical attic takes out about 5.4 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 19.2 days.
What to do about ice dams in State College
- 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.
State College winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 11.3 | 14.0 | 4.5 |
| February | 11.6 | 14.1 | 4.2 |
| March | 9.4 | 7.8 | 1.5 |
| April | 0.9 | 0.2 | 0.0 |
| October | 0.4 | 0.2 | 0.0 |
| November | 2.6 | 1.7 | 0.2 |
| December | 7.6 | 7.6 | 2.0 |
State College next to nearby towns
State College ranks 18 of 68 Pennsylvania cities here for ice-dam days, behind St. Marys at 26.9 days.
- Altoona, PA 35 mi, 14.6 days
- Williamsport, PA 53 mi, 10.0 days
- Carlisle, PA 53 mi, 6.9 days
- St. Marys, PA 57 mi, 26.9 days
- Mechanicsburg, PA 60 mi, 8.0 days
Where these numbers come from
NOAA 1991–2020 climate normals from State College, 0.6 miles from State College. 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.