Ice dam risk in Salt Lake City, UT
Will your roof get ice dams in Salt Lake City, UT?
11.0 dam days a winter
Moderate risk. On an ordinary house in Salt Lake City, conditions for an ice dam come on about 11.0 days in a normal winter, mostly in January and December.
Salt Lake City averages 52 inches of snow a year and about 45 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 Salt Lake City
| Attic | Dam days | Risk |
|---|---|---|
| Air-sealed and well insulated | 7.6 | Moderate |
| Typical, some insulation, not air-sealed | 11.0 | Moderate |
| Older or poorly insulated, warm attic | 15.3 | 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 15.3 days.
Preventing ice dams on a Salt Lake City 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.
Which to spend on first: air sealing or heat cable.
Salt Lake City winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 12.7 | 16.1 | 4.6 |
| February | 10.7 | 9.1 | 1.9 |
| March | 5.9 | 2.8 | 0.3 |
| April | 2.9 | 0.6 | 0.0 |
| May | 0.1 | 0.0 | 0.0 |
| October | 0.5 | 0.1 | 0.0 |
| November | 7.0 | 3.4 | 0.5 |
| December | 12.1 | 12.9 | 3.6 |
Salt Lake City next to nearby towns
Salt Lake City ranks 35 of 67 Utah cities here for ice-dam days, behind Ogden at 37.2 days.
- North Salt Lake, UT 5 mi, 16.0 days
- South Salt Lake, UT 5 mi, 8.6 days
- Woods Cross, UT 7 mi, 16.0 days
- West Valley City, UT 7 mi, 11.0 days
- Bountiful, UT 8 mi, 20.7 days
Where these numbers come from
NOAA 1991–2020 climate normals from Salt Lake City International Airport, 1.8 miles from Salt Lake City. 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.