Ice dam risk in Murray, UT
Ice dams in Murray, UT: how often
10.7 dam days a winter
Moderate risk. On an ordinary house in Murray, conditions for an ice dam come on about 10.7 days in a normal winter, mostly in January and December.
Murray averages 82 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 Murray
| Attic | Dam days | Risk |
|---|---|---|
| Air-sealed and well insulated | 7.3 | Moderate |
| Typical, some insulation, not air-sealed | 10.7 | Moderate |
| Older or poorly insulated, warm attic | 15.0 | 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 15.0 days.
Preventing ice dams on a Murray 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.
Murray winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 17.0 | 16.1 | 4.4 |
| February | 18.4 | 9.1 | 1.8 |
| March | 7.6 | 2.8 | 0.3 |
| April | 5.6 | 0.6 | 0.0 |
| May | 0.3 | 0.0 | 0.0 |
| October | 1.5 | 0.1 | 0.0 |
| November | 8.2 | 3.4 | 0.5 |
| December | 23.3 | 12.9 | 3.7 |
Murray next to nearby towns
Murray ranks 41 of 67 Utah cities here for ice-dam days, behind Ogden at 37.2 days.
- Midvale, UT 3 mi, 10.7 days
- Taylorsville, UT 3 mi, 11.0 days
- Holladay, UT 3 mi, 10.7 days
- South Salt Lake, UT 4 mi, 8.6 days
- Millcreek, UT 4 mi, 10.7 days
Where these numbers come from
NOAA 1991–2020 climate normals from Cottonwood Weir, 5.8 miles from Murray. 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.
- Snow-on-the-ground counts come from a second, nearby station, because the closest one does not record them.