Ice dam risk in East Lansing, MI
Ice dams in East Lansing, MI: how often
21.3 dam days a winter
High risk. On an ordinary house in East Lansing, conditions for an ice dam come on about 21.3 days in a normal winter, mostly in January and February.
East Lansing averages 36 inches of snow a year and about 66 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 Lansing
| Attic | Dam days | Risk |
|---|---|---|
| Air-sealed and well insulated | 10.3 | Moderate |
| Typical, some insulation, not air-sealed | 21.3 | High |
| Older or poorly insulated, warm attic | 35.0 | Severe |
Sealing and insulating a typical attic takes out about 11.0 days a winter here. It drops the risk from high to moderate. An older house with a warm attic should expect closer to 35.0 days.
What to do about ice dams in East Lansing
- 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 Lansing winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 14.1 | 22.4 | 8.4 |
| February | 7.3 | 18.7 | 6.4 |
| March | 4.2 | 8.5 | 2.0 |
| April | 0.9 | 0.6 | 0.1 |
| October | 0.3 | 0.0 | 0.0 |
| November | 1.8 | 2.7 | 0.4 |
| December | 7.4 | 13.0 | 4.0 |
East Lansing next to nearby towns
East Lansing ranks 26 of 90 Michigan cities here for ice-dam days, behind Sault Ste. Marie at 48.8 days.
- Lansing, MI 5 mi, 21.6 days
- Owosso, MI 23 mi, 22.5 days
- Ionia, MI 34 mi, 26.5 days
- Jackson, MI 35 mi, 18.6 days
- Fenton, MI 39 mi, 21.4 days
Where these numbers come from
NOAA 1991–2020 climate normals from East Lansing 4 S, 5.2 miles from East Lansing. 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.
- Snow-on-the-ground counts come from a second, nearby station, because the closest one does not record them.