Ice dam risk in Wisconsin Rapids, WI
Will your roof get ice dams in Wisconsin Rapids, WI?
37.8 dam days a winter
Severe risk. On an ordinary house in Wisconsin Rapids, conditions for an ice dam come on about 37.8 days in a normal winter, mostly in February and January.
Wisconsin Rapids averages 49 inches of snow a year and about 102 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 Wisconsin Rapids
| Attic | Dam days | Risk |
|---|---|---|
| Air-sealed and well insulated | 15.1 | High |
| Typical, some insulation, not air-sealed | 37.8 | Severe |
| Older or poorly insulated, warm attic | 66.2 | Severe |
Sealing and insulating a typical attic takes out about 22.7 days a winter here. It drops the risk from severe to high. An older house with a warm attic should expect closer to 66.2 days.
What to do about ice dams in Wisconsin Rapids
- 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 409 kWh a winter in Wisconsin Rapids, roughly $70 at 17 cents a kWh.
Which to spend on first: air sealing or heat cable.
Wisconsin Rapids winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 11.6 | 27.1 | 12.0 |
| February | 11.5 | 27.9 | 11.3 |
| March | 6.9 | 18.5 | 5.0 |
| April | 4.2 | 3.0 | 0.4 |
| October | 0.3 | 0.2 | 0.0 |
| November | 1.9 | 4.3 | 1.1 |
| December | 12.3 | 20.7 | 8.0 |
Wisconsin Rapids next to nearby towns
Wisconsin Rapids ranks 8 of 98 Wisconsin cities here for ice-dam days, behind Wausau at 41.6 days.
- Plover, WI 15 mi, 37.8 days
- Stevens Point, WI 16 mi, 37.8 days
- Marshfield, WI 25 mi, 37.5 days
- Weston, WI 37 mi, 41.6 days
- Wausau, WI 40 mi, 41.6 days
Where these numbers come from
NOAA 1991–2020 climate normals from Stevens Pt, 14.5 miles from Wisconsin 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.