Ice dam risk in Windsor, CO
Will your roof get ice dams in Windsor, CO?
11.6 dam days a winter
Moderate risk. On an ordinary house in Windsor, conditions for an ice dam come on about 11.6 days in a normal winter, mostly in January and December.
Windsor averages 48 inches of snow a year and about 44 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 Windsor
| Attic | Dam days | Risk |
|---|---|---|
| Air-sealed and well insulated | 8.9 | Moderate |
| Typical, some insulation, not air-sealed | 11.6 | Moderate |
| Older or poorly insulated, warm attic | 15.0 | Moderate |
Sealing and insulating a typical attic takes out about 2.7 days a winter here. It does not move the risk band, but it shortens every dam. An older house with a warm attic should expect closer to 15.0 days.
What to do about ice dams in Windsor
- 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.
Windsor winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 6.6 | 12.9 | 3.8 |
| February | 7.0 | 8.3 | 2.3 |
| March | 8.2 | 3.7 | 0.8 |
| April | 5.7 | 1.6 | 0.2 |
| May | 1.8 | 0.3 | 0.0 |
| September | 0.6 | 0.1 | 0.0 |
| October | 4.0 | 1.4 | 0.1 |
| November | 7.6 | 4.4 | 1.0 |
| December | 6.9 | 11.2 | 3.4 |
Windsor next to nearby towns
Windsor ranks 11 of 53 Colorado cities here for ice-dam days, behind Steamboat Springs at 51.0 days.
- Severance, CO 3 mi, 11.6 days
- Timnath, CO 5 mi, 11.6 days
- Greeley, CO 9 mi, 10.0 days
- Loveland, CO 9 mi, 12.7 days
- Fort Collins, CO 9 mi, 10.5 days
Where these numbers come from
NOAA 1991–2020 climate normals from Ft Collins 4 E, 8.8 miles from Windsor. 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.