Ice dam risk in Baraboo, WI
Will your roof get ice dams in Baraboo, WI?
26.0 dam days a winter
High risk. On an ordinary house in Baraboo, conditions for an ice dam come on about 26.0 days in a normal winter, mostly in February and January.
Baraboo averages 43 inches of snow a year and about 75 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 Baraboo
| Attic | Dam days | Risk |
|---|---|---|
| Air-sealed and well insulated | 12.2 | Moderate |
| Typical, some insulation, not air-sealed | 26.0 | High |
| Older or poorly insulated, warm attic | 43.3 | Severe |
Sealing and insulating a typical attic takes out about 13.8 days a winter here. It drops the risk from high to moderate. An older house with a warm attic should expect closer to 43.3 days.
What to do about ice dams in Baraboo
- 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.
Baraboo winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 11.3 | 21.8 | 8.8 |
| February | 10.1 | 22.6 | 8.2 |
| March | 5.9 | 10.9 | 2.7 |
| April | 2.6 | 1.6 | 0.2 |
| October | 0.4 | 0.2 | 0.0 |
| November | 2.1 | 3.0 | 0.7 |
| December | 10.3 | 15.3 | 5.3 |
Baraboo next to nearby towns
Baraboo ranks 47 of 98 Wisconsin cities here for ice-dam days, behind Wausau at 41.6 days.
- Reedsburg, WI 14 mi, 25.3 days
- Waunakee, WI 25 mi, 26.5 days
- DeForest, WI 26 mi, 28.8 days
- Middleton, WI 28 mi, 22.2 days
- Windsor, WI 28 mi, 28.8 days
Where these numbers come from
NOAA 1991–2020 climate normals from Baraboo Wwtp, 0.9 miles from Baraboo. 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.