Ice dam risk in Berthoud, CO
How often ice dams form in Berthoud
12.7 dam days a winter
Moderate risk. On an ordinary house in Berthoud, conditions for an ice dam come on about 12.7 days in a normal winter, mostly in January and December.
Berthoud averages 47 inches of snow a year and about 49 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 Berthoud
| Attic | Dam days | Risk |
|---|---|---|
| Air-sealed and well insulated | 10.1 | Moderate |
| Typical, some insulation, not air-sealed | 12.7 | Moderate |
| Older or poorly insulated, warm attic | 16.0 | High |
Sealing and insulating a typical attic takes out about 2.6 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 16.0 days.
What to do about ice dams in Berthoud
- 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.
Berthoud winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 6.0 | 12.7 | 3.7 |
| February | 8.2 | 10.3 | 2.9 |
| March | 7.9 | 4.4 | 1.0 |
| April | 5.7 | 2.3 | 0.3 |
| May | 1.1 | 0.4 | 0.0 |
| October | 3.5 | 1.7 | 0.2 |
| November | 7.0 | 5.1 | 1.2 |
| December | 7.6 | 12.0 | 3.5 |
Berthoud next to nearby towns
Berthoud ranks 10 of 53 Colorado cities here for ice-dam days, behind Steamboat Springs at 51.0 days.
- Johnstown, CO 3 mi, 12.7 days
- Firestone, CO 9 mi, 9.4 days
- Loveland, CO 10 mi, 12.7 days
- Longmont, CO 11 mi, 11.4 days
- Evans, CO 12 mi, 10.0 days
Where these numbers come from
NOAA 1991–2020 climate normals from Loveland 2N, 12.1 miles from Berthoud. 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.