Ice dam risk in East Grand Rapids, MI
How often ice dams form in East Grand Rapids
22.4 dam days a winter
High risk. On an ordinary house in East Grand Rapids, conditions for an ice dam come on about 22.4 days in a normal winter, mostly in January and February.
East Grand Rapids averages 75 inches of snow a year and about 73 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 East Grand Rapids
| Attic | Dam days | Risk |
|---|---|---|
| Air-sealed and well insulated | 11.5 | Moderate |
| Typical, some insulation, not air-sealed | 22.4 | High |
| Older or poorly insulated, warm attic | 35.9 | Severe |
Sealing and insulating a typical attic takes out about 10.8 days a winter here. It drops the risk from high to moderate. An older house with a warm attic should expect closer to 35.9 days.
Preventing ice dams on a East Grand Rapids 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.
East Grand Rapids winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 21.7 | 23.1 | 8.1 |
| February | 22.3 | 20.7 | 7.0 |
| March | 5.3 | 9.1 | 2.0 |
| April | 2.6 | 1.1 | 0.1 |
| November | 6.0 | 3.2 | 0.5 |
| December | 17.0 | 15.4 | 4.6 |
East Grand Rapids next to nearby towns
East Grand Rapids ranks 15 of 90 Michigan cities here for ice-dam days, behind Sault Ste. Marie at 48.8 days.
- Grand Rapids, MI 3 mi, 22.4 days
- Kentwood, MI 4 mi, 21.5 days
- Wyoming, MI 6 mi, 22.4 days
- Grandville, MI 8 mi, 22.4 days
- Walker, MI 8 mi, 22.4 days
Where these numbers come from
NOAA 1991–2020 climate normals from E Grand Rapids, 0.7 miles from East Grand Rapids. 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.