Ice dam risk in Eagle Mountain, UT
Ice dams in Eagle Mountain, UT: how often
13.9 dam days a winter
Moderate risk. On an ordinary house in Eagle Mountain, conditions for an ice dam come on about 13.9 days in a normal winter, mostly in January and February.
Eagle Mountain averages 34 inches of snow a year and about 50 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 Eagle Mountain
| Attic | Dam days | Risk |
|---|---|---|
| Air-sealed and well insulated | 10.5 | Moderate |
| Typical, some insulation, not air-sealed | 13.9 | Moderate |
| Older or poorly insulated, warm attic | 18.1 | High |
Sealing and insulating a typical attic takes out about 3.4 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 18.1 days.
What to do about ice dams in Eagle Mountain
- 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.
Eagle Mountain winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 10.7 | 18.9 | 5.6 |
| February | 5.9 | 14.0 | 3.6 |
| March | 3.5 | 1.8 | 0.4 |
| April | 1.4 | 0.0 | 0.0 |
| May | 0.1 | 0.0 | 0.0 |
| October | 0.7 | 0.3 | 0.1 |
| November | 3.4 | 2.4 | 0.6 |
| December | 7.9 | 12.3 | 3.7 |
Eagle Mountain next to nearby towns
Eagle Mountain ranks 33 of 67 Utah cities here for ice-dam days, behind Ogden at 37.2 days.
- Saratoga Springs, UT 5 mi, 8.5 days
- Lehi, UT 10 mi, 17.2 days
- Bluffdale, UT 12 mi, 17.2 days
- American Fork, UT 12 mi, 8.2 days
- Herriman, UT 12 mi, 17.2 days
Where these numbers come from
NOAA 1991–2020 climate normals from Fairfield, 5.5 miles from Eagle Mountain. 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.