Ice dam risk in Ogden, UT
Ice dams in Ogden, UT: how often
37.2 dam days a winter
Severe risk. On an ordinary house in Ogden, conditions for an ice dam come on about 37.2 days in a normal winter, mostly in January and December.
Ogden averages 108 inches of snow a year and about 116 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 Ogden
| Attic | Dam days | Risk |
|---|---|---|
| Air-sealed and well insulated | 21.9 | High |
| Typical, some insulation, not air-sealed | 37.2 | Severe |
| Older or poorly insulated, warm attic | 56.3 | Severe |
Sealing and insulating a typical attic takes out about 15.3 days a winter here. It drops the risk from severe to high. An older house with a warm attic should expect closer to 56.3 days.
Preventing ice dams on a Ogden 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.
- Heat cable is worth pricing here even on a sealed house, along the eave and in the gutters and downspouts it drains into.
Running 60 feet of 5 W/ft cable whenever snow lies below freezing would use about 275 kWh a winter in Ogden, roughly $47 at 17 cents a kWh.
Which to spend on first: air sealing or heat cable.
Ogden winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 28.7 | 30.3 | 11.2 |
| February | 23.1 | 26.3 | 8.5 |
| March | 11.6 | 19.3 | 4.6 |
| April | 5.5 | 3.6 | 0.6 |
| May | 0.2 | 0.2 | 0.0 |
| October | 0.9 | 0.9 | 0.1 |
| November | 11.6 | 8.4 | 2.1 |
| December | 26.3 | 27.0 | 10.0 |
Ogden next to nearby towns
Ogden ranks 1 of 67 Utah cities here for ice-dam days, the worst in the state.
- South Ogden, UT 4 mi, 6.7 days
- West Haven, UT 5 mi, 6.7 days
- Roy, UT 6 mi, 6.7 days
- North Ogden, UT 6 mi, 37.2 days
- Pleasant View, UT 7 mi, 37.2 days
Where these numbers come from
NOAA 1991–2020 climate normals from Pineview Dam, 7.1 miles from Ogden. 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.