Ice dam risk in Farmington, MO
Will your roof get ice dams in Farmington, MO?
2.5 dam days a winter
Low risk. On an ordinary house in Farmington, conditions for an ice dam come on about 2.5 days in a normal winter, mostly in January and February.
Farmington averages 9 inches of snow a year and about 11 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 Farmington
| Attic | Dam days | Risk |
|---|---|---|
| Air-sealed and well insulated | 1.8 | Low |
| Typical, some insulation, not air-sealed | 2.5 | Low |
| Older or poorly insulated, warm attic | 3.4 | Low |
The attic matters less in Farmington than in colder towns: there are only 0.7 days a winter between a typical attic and a sealed one.
What to do about ice dams in Farmington
- Check the gutters before the first snow and clear them, so meltwater has somewhere to go. If you see icicles thicker than a finger along the eave after a storm, that is the early sign to look at the attic.
Snowy places are not always the worst: why snowfall misleads.
Farmington winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 2.7 | 3.8 | 1.0 |
| February | 2.1 | 3.3 | 0.7 |
| March | 1.0 | 0.8 | 0.1 |
| November | 0.1 | 0.3 | 0.0 |
| December | 2.8 | 2.7 | 0.6 |
Farmington next to nearby towns
Farmington ranks 65 of 80 Missouri cities here for ice-dam days, behind Maryville at 9.3 days.
- Festus, MO 30 mi, 2.1 days
- Waterloo, IL 41 mi, 2.1 days
- Arnold, MO 45 mi, 2.1 days
- Columbia, IL 48 mi, 3.6 days
- Jackson, MO 51 mi, 2.1 days
Where these numbers come from
NOAA 1991–2020 climate normals from Farmington, 1.2 miles from Farmington. 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.