Ice dam risk in East Moline, IL
Will your roof get ice dams in East Moline, IL?
15.9 dam days a winter
High risk. On an ordinary house in East Moline, conditions for an ice dam come on about 15.9 days in a normal winter, mostly in January and February.
East Moline averages 36 inches of snow a year and about 51 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 East Moline
| Attic | Dam days | Risk |
|---|---|---|
| Air-sealed and well insulated | 8.1 | Moderate |
| Typical, some insulation, not air-sealed | 15.9 | High |
| Older or poorly insulated, warm attic | 25.7 | High |
Sealing and insulating a typical attic takes out about 7.9 days a winter here. It drops the risk from high to moderate. An older house with a warm attic should expect closer to 25.7 days.
Preventing ice dams on a East Moline 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 Moline winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 10.8 | 20.2 | 7.2 |
| February | 8.6 | 13.8 | 4.3 |
| March | 4.4 | 4.2 | 0.8 |
| April | 1.1 | 0.2 | 0.0 |
| October | 0.3 | 0.1 | 0.0 |
| November | 2.1 | 1.7 | 0.3 |
| December | 8.8 | 11.1 | 3.3 |
East Moline next to nearby towns
East Moline ranks 58 of 225 Illinois cities here for ice-dam days, behind Arlington Heights at 21.5 days.
- Bettendorf, IA 6 mi, 15.9 days
- Moline, IL 6 mi, 15.9 days
- Rock Island, IL 11 mi, 14.0 days
- Davenport, IA 11 mi, 14.0 days
- Clinton, IA 24 mi, 16.6 days
Where these numbers come from
NOAA 1991–2020 climate normals from Moline Quad City International Airport, 8.6 miles from East Moline. 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.