Ice dam risk in Wixom, MI
How often ice dams form in Wixom
18.1 dam days a winter
High risk. On an ordinary house in Wixom, conditions for an ice dam come on about 18.1 days in a normal winter, mostly in February and January.
Wixom averages 36 inches of snow a year and about 53 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 Wixom
| Attic | Dam days | Risk |
|---|---|---|
| Air-sealed and well insulated | 8.3 | Moderate |
| Typical, some insulation, not air-sealed | 18.1 | High |
| Older or poorly insulated, warm attic | 30.4 | High |
Sealing and insulating a typical attic takes out about 9.8 days a winter here. It drops the risk from high to moderate. An older house with a warm attic should expect closer to 30.4 days.
Preventing ice dams on a Wixom 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.
Wixom winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 9.8 | 16.4 | 6.3 |
| February | 10.6 | 18.4 | 6.7 |
| March | 4.7 | 5.8 | 1.4 |
| April | 1.5 | 0.4 | 0.0 |
| November | 2.3 | 1.5 | 0.3 |
| December | 7.1 | 10.4 | 3.4 |
Wixom next to nearby towns
Wixom ranks 50 of 90 Michigan cities here for ice-dam days, behind Sault Ste. Marie at 48.8 days.
- Novi, MI 4 mi, 18.1 days
- South Lyon, MI 8 mi, 18.3 days
- Farmington Hills, MI 8 mi, 18.1 days
- Farmington, MI 9 mi, 18.1 days
- Livonia, MI 12 mi, 18.1 days
Where these numbers come from
NOAA 1991–2020 climate normals from Farmington, 9.4 miles from Wixom. 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.