Ice dam risk in Hutchinson, MN
Ice dams in Hutchinson, MN: how often
35.5 dam days a winter
Severe risk. On an ordinary house in Hutchinson, conditions for an ice dam come on about 35.5 days in a normal winter, mostly in January and February.
Hutchinson averages 50 inches of snow a year and about 92 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 Hutchinson
| Attic | Dam days | Risk |
|---|---|---|
| Air-sealed and well insulated | 13.0 | Moderate |
| Typical, some insulation, not air-sealed | 35.5 | Severe |
| Older or poorly insulated, warm attic | 63.7 | Severe |
Sealing and insulating a typical attic takes out about 22.5 days a winter here. It drops the risk from severe to moderate. An older house with a warm attic should expect closer to 63.7 days.
Preventing ice dams on a Hutchinson 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.
Hutchinson winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 6.9 | 26.4 | 11.9 |
| February | 11.8 | 22.5 | 9.6 |
| March | 7.6 | 15.1 | 4.2 |
| April | 7.0 | 3.5 | 0.4 |
| May | 0.1 | 0.1 | 0.0 |
| October | 0.8 | 0.6 | 0.1 |
| November | 3.6 | 4.4 | 1.1 |
| December | 12.2 | 19.7 | 8.2 |
Hutchinson next to nearby towns
Hutchinson ranks 49 of 103 Minnesota cities here for ice-dam days, behind Hermantown at 52.9 days.
- Waconia, MN 29 mi, 32.4 days
- Buffalo, MN 32 mi, 36.4 days
- Victoria, MN 35 mi, 32.4 days
- Willmar, MN 37 mi, 37.6 days
- Chaska, MN 38 mi, 32.4 days
Where these numbers come from
NOAA 1991–2020 climate normals from Brownton Wwtp, 10.6 miles from Hutchinson. 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.