Ice dam risk in Logan, UT
Ice dams in Logan, UT: how often
23.3 dam days a winter
High risk. On an ordinary house in Logan, conditions for an ice dam come on about 23.3 days in a normal winter, mostly in January and December.
Logan averages 44 inches of snow a year and about 73 days with snow on the ground. Snow that lies that long is what turns a little attic heat into a ridge of ice at the eave. 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 Logan
| Attic | Dam days | Risk |
|---|---|---|
| Air-sealed and well insulated | 12.9 | Moderate |
| Typical, some insulation, not air-sealed | 23.3 | High |
| Older or poorly insulated, warm attic | 36.2 | Severe |
Sealing and insulating a typical attic takes out about 10.4 days a winter here. It drops the risk from high to moderate. An older house with a warm attic should expect closer to 36.2 days.
Preventing ice dams on a Logan roof
- 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.
- At the next reroof, ask for ice-and-water membrane under the shingles from the eave to at least 24 inches inside the wall line. It does not stop a dam; it stops the leak when one forms.
Which to spend on first: air sealing or heat cable.
Logan winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 13.9 | 24.0 | 8.7 |
| February | 8.3 | 17.9 | 5.6 |
| March | 3.9 | 7.2 | 1.5 |
| April | 2.5 | 1.1 | 0.1 |
| October | 0.7 | 0.4 | 0.0 |
| November | 4.0 | 3.7 | 0.9 |
| December | 10.7 | 18.6 | 6.4 |
Logan next to nearby towns
Logan ranks 5 of 67 Utah cities here for ice-dam days, behind Ogden at 37.2 days.
- North Logan, UT 3 mi, 23.3 days
- Smithfield, UT 7 mi, 23.2 days
- Hyrum, UT 7 mi, 24.8 days
- Tremonton, UT 18 mi, 15.7 days
- Brigham City, UT 19 mi, 14.3 days
Where these numbers come from
NOAA 1991–2020 climate normals from Logan Radio Kvnu, 0.8 miles from Logan. 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.