Ice dam risk in Austin, MN
Ice dams in Austin, MN: how often
33.8 dam days a winter
High risk. On an ordinary house in Austin, conditions for an ice dam come on about 33.8 days in a normal winter, mostly in February and January.
Austin averages 43 inches of snow a year and about 88 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 Austin
| Attic | Dam days | Risk |
|---|---|---|
| Air-sealed and well insulated | 12.8 | Moderate |
| Typical, some insulation, not air-sealed | 33.8 | High |
| Older or poorly insulated, warm attic | 60.1 | Severe |
Sealing and insulating a typical attic takes out about 21.0 days a winter here. It drops the risk from high to moderate. An older house with a warm attic should expect closer to 60.1 days.
What to do about ice dams in Austin
- 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.
Austin winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 11.0 | 24.0 | 10.7 |
| February | 10.4 | 25.4 | 10.4 |
| March | 7.5 | 15.2 | 4.3 |
| April | 2.2 | 1.9 | 0.2 |
| May | 0.3 | 0.1 | 0.0 |
| October | 0.4 | 0.1 | 0.0 |
| November | 2.3 | 3.0 | 0.8 |
| December | 9.3 | 18.6 | 7.4 |
Austin next to nearby towns
Austin ranks 55 of 103 Minnesota cities here for ice-dam days, behind Hermantown at 52.9 days.
- Albert Lea, MN 19 mi, 31.7 days
- Owatonna, MN 32 mi, 33.5 days
- Rochester, MN 34 mi, 33.3 days
- Mason City, IA 38 mi, 28.7 days
- Faribault, MN 46 mi, 33.6 days
Where these numbers come from
NOAA 1991–2020 climate normals from Austin Waste Wtp Facility, 1.3 miles from Austin. 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.