Ice dam risk in Norwalk, OH
Will your roof get ice dams in Norwalk, OH?
12.6 dam days a winter
Moderate risk. On an ordinary house in Norwalk, conditions for an ice dam come on about 12.6 days in a normal winter, mostly in January and February.
Norwalk averages 33 inches of snow a year and about 43 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 Norwalk
| Attic | Dam days | Risk |
|---|---|---|
| Air-sealed and well insulated | 6.3 | Moderate |
| Typical, some insulation, not air-sealed | 12.6 | Moderate |
| Older or poorly insulated, warm attic | 20.4 | High |
Sealing and insulating a typical attic takes out about 6.2 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 20.4 days.
What to do about ice dams in Norwalk
- 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.
Norwalk winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 9.7 | 15.4 | 5.3 |
| February | 8.2 | 12.1 | 3.9 |
| March | 5.1 | 5.6 | 1.2 |
| April | 1.6 | 0.6 | 0.0 |
| November | 1.5 | 1.5 | 0.2 |
| December | 6.6 | 7.5 | 2.0 |
Norwalk next to nearby towns
Norwalk ranks 77 of 176 Ohio cities here for ice-dam days, behind Euclid at 24.8 days.
- Sandusky, OH 16 mi, 12.6 days
- Vermilion, OH 19 mi, 15.3 days
- Amherst, OH 23 mi, 15.3 days
- Lorain, OH 26 mi, 11.3 days
- Fremont, OH 27 mi, 10.0 days
Where these numbers come from
NOAA 1991–2020 climate normals from Norwalk Wwtp, 1.3 miles from Norwalk. 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.