Ice dam risk in Manhattan, KS
Will your roof get ice dams in Manhattan, KS?
5.4 dam days a winter
Moderate risk. On an ordinary house in Manhattan, conditions for an ice dam come on about 5.4 days in a normal winter, mostly in January and December.
Manhattan averages 18 inches of snow a year and about 20 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 Manhattan
| Attic | Dam days | Risk |
|---|---|---|
| Air-sealed and well insulated | 3.7 | Low |
| Typical, some insulation, not air-sealed | 5.4 | Moderate |
| Older or poorly insulated, warm attic | 7.4 | Moderate |
The attic matters less in Manhattan than in colder towns: there are only 1.7 days a winter between a typical attic and a sealed one.
Preventing ice dams on a Manhattan roof
- 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.
Manhattan winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 4.8 | 7.6 | 2.3 |
| February | 5.0 | 5.4 | 1.4 |
| March | 1.8 | 1.1 | 0.2 |
| April | 0.1 | 0.0 | 0.0 |
| November | 1.1 | 0.7 | 0.1 |
| December | 4.8 | 5.5 | 1.5 |
Manhattan next to nearby towns
Manhattan ranks 4 of 38 Kansas cities here for ice-dam days, behind Salina at 5.8 days.
- Junction City, KS 17 mi, 5.7 days
- Topeka, KS 50 mi, 4.5 days
- Emporia, KS 59 mi, 4.4 days
- Salina, KS 60 mi, 5.8 days
- Lawrence, KS 74 mi, 3.1 days
Where these numbers come from
NOAA 1991–2020 climate normals from Manhattan, 1.4 miles from Manhattan. 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.