Ice dam risk in West Fargo, ND
Ice dams in West Fargo, ND: how often
41.7 dam days a winter
Severe risk. On an ordinary house in West Fargo, conditions for an ice dam come on about 41.7 days in a normal winter, mostly in January and February.
West Fargo averages 51 inches of snow a year and about 107 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 West Fargo
| Attic | Dam days | Risk |
|---|---|---|
| Air-sealed and well insulated | 14.7 | Moderate |
| Typical, some insulation, not air-sealed | 41.7 | Severe |
| Older or poorly insulated, warm attic | 75.4 | Severe |
Sealing and insulating a typical attic takes out about 27.0 days a winter here. It drops the risk from severe to moderate. An older house with a warm attic should expect closer to 75.4 days.
Preventing ice dams on a West Fargo 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.
West Fargo winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 10.3 | 28.8 | 13.1 |
| February | 8.1 | 24.7 | 10.6 |
| March | 9.2 | 17.9 | 5.5 |
| April | 4.1 | 4.7 | 0.7 |
| October | 1.2 | 0.9 | 0.1 |
| November | 6.8 | 8.6 | 2.6 |
| December | 11.7 | 21.5 | 9.2 |
West Fargo next to nearby towns
West Fargo ranks 5 of 9 North Dakota cities here for ice-dam days, behind Jamestown at 45.7 days.
- Fargo, ND 4 mi, 43.6 days
- Moorhead, MN 8 mi, 43.6 days
- Detroit Lakes, MN 50 mi, 46.7 days
- Fergus Falls, MN 56 mi, 47.3 days
- Grand Forks, ND 74 mi, 44.3 days
Where these numbers come from
NOAA 1991–2020 climate normals from Fargo Hector International Airport, 6.4 miles from West Fargo. 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.