IceDamCheck

Ice dam risk in Little Canada, MN

Will your roof get ice dams in Little Canada, MN?

22.8 dam days a winter

High risk. On an ordinary house in Little Canada, conditions for an ice dam come on about 22.8 days in a normal winter, mostly in January and February.

Little Canada averages 40 inches of snow a year and about 62 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 Little Canada

AtticDam daysRisk
Air-sealed and well insulated8.9Moderate
Typical, some insulation, not air-sealed22.8High
Older or poorly insulated, warm attic40.2Severe

Sealing and insulating a typical attic takes out about 13.9 days a winter here. It drops the risk from high to moderate. An older house with a warm attic should expect closer to 40.2 days.

What to do about ice dams in Little Canada

  1. 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.
  2. 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.
  3. 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.

Little Canada winter, month by month

MonthSnow (in)Days on groundDam days
January8.319.68.5
February12.316.46.4
March4.09.12.3
April2.11.70.2
October0.50.40.0
November3.02.50.6
December10.212.24.8

Little Canada next to nearby towns

Little Canada ranks 103 of 103 Minnesota cities here for ice-dam days, behind Hermantown at 52.9 days.

Where these numbers come from

NOAA 1991–2020 climate normals from U Of Mn St Paul, 5.2 miles from Little Canada. 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.