Ice dam risk in Brainerd, MN
Will your roof get ice dams in Brainerd, MN?
46.1 dam days a winter
Severe risk. On an ordinary house in Brainerd, conditions for an ice dam come on about 46.1 days in a normal winter, mostly in January and February.
Brainerd averages 48 inches of snow a year and about 118 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 Brainerd
| Attic | Dam days | Risk |
|---|---|---|
| Air-sealed and well insulated | 17.5 | High |
| Typical, some insulation, not air-sealed | 46.1 | Severe |
| Older or poorly insulated, warm attic | 82.0 | Severe |
Sealing and insulating a typical attic takes out about 28.7 days a winter here. It drops the risk from severe to high. An older house with a warm attic should expect closer to 82.0 days.
Preventing ice dams on a Brainerd 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.
- 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 516 kWh a winter in Brainerd, roughly $88 at 17 cents a kWh.
Which to spend on first: air sealing or heat cable.
Brainerd winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 10.0 | 28.7 | 13.3 |
| February | 8.3 | 27.3 | 11.5 |
| March | 9.2 | 21.8 | 6.6 |
| April | 4.3 | 4.8 | 0.9 |
| October | 0.7 | 0.6 | 0.1 |
| November | 5.7 | 10.2 | 3.2 |
| December | 10.0 | 24.7 | 10.7 |
Brainerd next to nearby towns
Brainerd ranks 8 of 103 Minnesota cities here for ice-dam days, behind Hermantown at 52.9 days.
- Sartell, MN 51 mi, 39.1 days
- Sauk Rapids, MN 53 mi, 38.6 days
- St. Cloud, MN 57 mi, 38.6 days
- Alexandria, MN 65 mi, 40.8 days
- Grand Rapids, MN 69 mi, 49.9 days
Where these numbers come from
NOAA 1991–2020 climate normals from Brainerd, 1.0 miles from Brainerd. 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.