Ice dam risk in Willoughby, OH
How often ice dams form in Willoughby
24.8 dam days a winter
High risk. On an ordinary house in Willoughby, conditions for an ice dam come on about 24.8 days in a normal winter, mostly in January and February.
Willoughby averages 114 inches of snow a year and about 82 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 Willoughby
| Attic | Dam days | Risk |
|---|---|---|
| Air-sealed and well insulated | 12.6 | Moderate |
| Typical, some insulation, not air-sealed | 24.8 | High |
| Older or poorly insulated, warm attic | 40.1 | Severe |
Sealing and insulating a typical attic takes out about 12.2 days a winter here. It drops the risk from high to moderate. An older house with a warm attic should expect closer to 40.1 days.
Preventing ice dams on a Willoughby 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.
Willoughby winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 34.4 | 23.9 | 8.6 |
| February | 23.4 | 20.9 | 7.1 |
| March | 16.5 | 13.3 | 3.3 |
| April | 4.0 | 1.6 | 0.2 |
| October | 0.6 | 0.3 | 0.0 |
| November | 9.3 | 5.6 | 0.9 |
| December | 25.5 | 16.6 | 4.8 |
Willoughby next to nearby towns
Willoughby ranks 3 of 176 Ohio cities here for ice-dam days, behind Euclid at 24.8 days.
- Eastlake, OH 1 mi, 24.8 days
- Willowick, OH 3 mi, 24.8 days
- Wickliffe, OH 4 mi, 24.8 days
- Mentor, OH 5 mi, 24.8 days
- Euclid, OH 7 mi, 24.8 days
Where these numbers come from
NOAA 1991–2020 climate normals from Chardon, 12.2 miles from Willoughby. 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.