Ice dam risk in Mooresville, IN
Ice dams in Mooresville, IN: how often
7.0 dam days a winter
Moderate risk. On an ordinary house in Mooresville, conditions for an ice dam come on about 7.0 days in a normal winter, mostly in January and February.
Mooresville averages 26 inches of snow a year and about 27 days with snow on the ground. Most of it comes and goes within a few days. 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 Mooresville
| Attic | Dam days | Risk |
|---|---|---|
| Air-sealed and well insulated | 3.9 | Low |
| Typical, some insulation, not air-sealed | 7.0 | Moderate |
| Older or poorly insulated, warm attic | 10.8 | Moderate |
Sealing and insulating a typical attic takes out about 3.0 days a winter here. It drops the risk from moderate to low. An older house with a warm attic should expect closer to 10.8 days.
Preventing ice dams on a Mooresville 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.
Which to spend on first: air sealing or heat cable.
Mooresville winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 8.8 | 10.8 | 3.3 |
| February | 6.0 | 7.1 | 1.9 |
| March | 3.2 | 1.9 | 0.3 |
| April | 0.2 | 0.1 | 0.0 |
| October | 0.1 | 0.0 | 0.0 |
| November | 0.8 | 0.4 | 0.0 |
| December | 6.4 | 6.3 | 1.5 |
Mooresville next to nearby towns
Mooresville ranks 66 of 88 Indiana cities here for ice-dam days, behind Plymouth at 15.9 days.
- Plainfield, IN 6 mi, 7.0 days
- Bargersville, IN 10 mi, 6.0 days
- Avon, IN 11 mi, 7.0 days
- Danville, IN 13 mi, 7.0 days
- Martinsville, IN 13 mi, 5.1 days
Where these numbers come from
NOAA 1991–2020 climate normals from Indianapolis, 8.6 miles from Mooresville. 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.