Ice dam risk in Saginaw, MI
Will your roof get ice dams in Saginaw, MI?
21.6 dam days a winter
High risk. On an ordinary house in Saginaw, conditions for an ice dam come on about 21.6 days in a normal winter, mostly in January and February.
Saginaw averages 41 inches of snow a year and about 65 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 Saginaw
| Attic | Dam days | Risk |
|---|---|---|
| Air-sealed and well insulated | 10.2 | Moderate |
| Typical, some insulation, not air-sealed | 21.6 | High |
| Older or poorly insulated, warm attic | 36.0 | Severe |
Sealing and insulating a typical attic takes out about 11.5 days a winter here. It drops the risk from high to moderate. An older house with a warm attic should expect closer to 36.0 days.
Preventing ice dams on a Saginaw 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.
Saginaw winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 11.4 | 20.9 | 8.1 |
| February | 9.1 | 18.6 | 6.7 |
| March | 5.0 | 9.3 | 2.3 |
| April | 1.3 | 1.1 | 0.1 |
| October | 0.2 | 0.0 | 0.0 |
| November | 2.3 | 2.5 | 0.4 |
| December | 11.4 | 12.7 | 4.1 |
Saginaw next to nearby towns
Saginaw ranks 20 of 90 Michigan cities here for ice-dam days, behind Sault Ste. Marie at 48.8 days.
- Bay City, MI 12 mi, 21.6 days
- Midland, MI 20 mi, 21.6 days
- Flint, MI 30 mi, 19.5 days
- Owosso, MI 31 mi, 22.5 days
- Burton, MI 33 mi, 21.4 days
Where these numbers come from
NOAA 1991–2020 climate normals from Saginaw #3, 0.4 miles from Saginaw. 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.