Ice dam risk in Rolla, MO
Will your roof get ice dams in Rolla, MO?
4.1 dam days a winter
Low risk. On an ordinary house in Rolla, conditions for an ice dam come on about 4.1 days in a normal winter, mostly in January and February.
Rolla averages 17 inches of snow a year and about 18 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 Rolla
| Attic | Dam days | Risk |
|---|---|---|
| Air-sealed and well insulated | 2.7 | Low |
| Typical, some insulation, not air-sealed | 4.1 | Low |
| Older or poorly insulated, warm attic | 5.8 | Moderate |
The attic matters less in Rolla than in colder towns: there are only 1.4 days a winter between a typical attic and a sealed one.
What to do about ice dams in Rolla
- 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.
Rolla winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 5.6 | 6.8 | 1.9 |
| February | 4.1 | 4.8 | 1.1 |
| March | 2.6 | 1.5 | 0.2 |
| April | 0.2 | 0.0 | 0.0 |
| October | 0.1 | 0.0 | 0.0 |
| November | 1.3 | 0.8 | 0.1 |
| December | 3.4 | 4.1 | 0.9 |
Rolla next to nearby towns
Rolla ranks 30 of 80 Missouri cities here for ice-dam days, behind Maryville at 9.3 days.
- Jefferson City, MO 48 mi, 4.1 days
- Lebanon, MO 53 mi, 2.6 days
- Union, MO 54 mi, 3.1 days
- Washington, MO 58 mi, 3.7 days
- Fulton, MO 64 mi, 6.3 days
Where these numbers come from
NOAA 1991–2020 climate normals from Rolla Missouri S&t, 1.1 miles from Rolla. 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.