Ice dam risk in Scranton, PA
How often ice dams form in Scranton
19.4 dam days a winter
High risk. On an ordinary house in Scranton, conditions for an ice dam come on about 19.4 days in a normal winter, mostly in February and January.
Scranton averages 45 inches of snow a year and about 71 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 Scranton
| Attic | Dam days | Risk |
|---|---|---|
| Air-sealed and well insulated | 11.0 | Moderate |
| Typical, some insulation, not air-sealed | 19.4 | High |
| Older or poorly insulated, warm attic | 29.9 | High |
Sealing and insulating a typical attic takes out about 8.4 days a winter here. It drops the risk from high to moderate. An older house with a warm attic should expect closer to 29.9 days.
Preventing ice dams on a Scranton 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.
Scranton winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 11.7 | 21.0 | 6.8 |
| February | 10.9 | 21.5 | 6.3 |
| March | 10.1 | 14.3 | 2.8 |
| April | 0.8 | 0.5 | 0.0 |
| October | 0.7 | 0.0 | 0.0 |
| November | 3.2 | 1.2 | 0.2 |
| December | 7.7 | 12.8 | 3.3 |
Scranton next to nearby towns
Scranton ranks 4 of 68 Pennsylvania cities here for ice-dam days, behind St. Marys at 26.9 days.
- Dunmore, PA 3 mi, 19.4 days
- Kingston, PA 15 mi, 14.4 days
- Wilkes-Barre, PA 15 mi, 14.4 days
- Nanticoke, PA 22 mi, 14.4 days
- Hazleton, PA 35 mi, 17.9 days
Where these numbers come from
NOAA 1991–2020 climate normals from Wilkes-Barre/Scranton International Airport, 5.7 miles from Scranton. 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.
- Snow-on-the-ground counts come from a second, nearby station, because the closest one does not record them.