Ice dam risk in Mount Vernon, OH
Will your roof get ice dams in Mount Vernon, OH?
12.6 dam days a winter
Moderate risk. On an ordinary house in Mount Vernon, conditions for an ice dam come on about 12.6 days in a normal winter, mostly in January and February.
Mount Vernon averages 42 inches of snow a year and about 44 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 Mount Vernon
| Attic | Dam days | Risk |
|---|---|---|
| Air-sealed and well insulated | 7.2 | Moderate |
| Typical, some insulation, not air-sealed | 12.6 | Moderate |
| Older or poorly insulated, warm attic | 19.4 | 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 19.4 days.
What to do about ice dams in Mount Vernon
- 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.
Mount Vernon winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 12.9 | 15.5 | 5.1 |
| February | 10.6 | 11.9 | 3.6 |
| March | 6.5 | 5.1 | 1.1 |
| April | 1.2 | 0.7 | 0.1 |
| November | 2.3 | 2.1 | 0.4 |
| December | 8.1 | 8.9 | 2.4 |
Mount Vernon next to nearby towns
Mount Vernon ranks 76 of 176 Ohio cities here for ice-dam days, behind Euclid at 24.8 days.
- Newark, OH 22 mi, 6.8 days
- Heath, OH 25 mi, 6.8 days
- New Albany, OH 26 mi, 6.7 days
- Mansfield, OH 27 mi, 13.8 days
- Pataskala, OH 28 mi, 6.7 days
Where these numbers come from
NOAA 1991–2020 climate normals from Danville 2 W, 9.7 miles from Mount Vernon. 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.