Ice dam risk in Traverse City, MI
How often ice dams form in Traverse City
35.2 dam days a winter
Severe risk. On an ordinary house in Traverse City, conditions for an ice dam come on about 35.2 days in a normal winter, mostly in January and February.
Traverse City averages 101 inches of snow a year and about 103 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 Traverse City
| Attic | Dam days | Risk |
|---|---|---|
| Air-sealed and well insulated | 15.4 | High |
| Typical, some insulation, not air-sealed | 35.2 | Severe |
| Older or poorly insulated, warm attic | 59.9 | Severe |
Sealing and insulating a typical attic takes out about 19.8 days a winter here. It drops the risk from severe to high. An older house with a warm attic should expect closer to 59.9 days.
What to do about ice dams in Traverse City
- 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.
- Heat cable is worth pricing here even on a sealed house, along the eave and in the gutters and downspouts it drains into.
Running 60 feet of 5 W/ft cable whenever snow lies below freezing would use about 356 kWh a winter in Traverse City, roughly $61 at 17 cents a kWh.
Which to spend on first: air sealing or heat cable.
Traverse City winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 32.3 | 28.0 | 11.3 |
| February | 21.4 | 27.2 | 10.6 |
| March | 12.3 | 19.6 | 5.4 |
| April | 4.7 | 3.5 | 0.6 |
| October | 0.1 | 0.1 | 0.0 |
| November | 5.6 | 4.6 | 0.8 |
| December | 24.6 | 19.5 | 6.5 |
Traverse City next to nearby towns
Traverse City ranks 4 of 90 Michigan cities here for ice-dam days, behind Sault Ste. Marie at 48.8 days.
- Cadillac, MI 36 mi, 38.5 days
- Mount Pleasant, MI 90 mi, 24.7 days
- Escanaba, MI 99 mi, 34.4 days
- Marinette, WI 102 mi, 31.3 days
- Midland, MI 103 mi, 21.6 days
Where these numbers come from
NOAA 1991–2020 climate normals from Traverse City Munson, 2.1 miles from Traverse City. 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.