Ice dam risk in Lone Tree, CO
Ice dams in Lone Tree, CO: how often
11.5 dam days a winter
Moderate risk. On an ordinary house in Lone Tree, conditions for an ice dam come on about 11.5 days in a normal winter, mostly in January and December.
Lone Tree averages 58 inches of snow a year and about 48 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 Lone Tree
| Attic | Dam days | Risk |
|---|---|---|
| Air-sealed and well insulated | 9.4 | Moderate |
| Typical, some insulation, not air-sealed | 11.5 | Moderate |
| Older or poorly insulated, warm attic | 14.0 | Moderate |
Sealing and insulating a typical attic takes out about 2.0 days a winter here. It does not move the risk band, but it shortens every dam.
Preventing ice dams on a Lone Tree 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.
Lone Tree winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 8.0 | 11.7 | 3.2 |
| February | 10.7 | 9.3 | 2.5 |
| March | 10.7 | 5.2 | 1.1 |
| April | 8.3 | 3.6 | 0.5 |
| May | 1.1 | 0.5 | 0.0 |
| September | 0.4 | 0.1 | 0.0 |
| October | 2.7 | 1.8 | 0.2 |
| November | 6.7 | 4.5 | 1.0 |
| December | 8.9 | 11.4 | 3.1 |
Lone Tree next to nearby towns
Lone Tree ranks 18 of 53 Colorado cities here for ice-dam days, behind Steamboat Springs at 51.0 days.
- Centennial, CO 4 mi, 7.2 days
- Castle Pines, CO 5 mi, 11.5 days
- Parker, CO 5 mi, 11.5 days
- Greenwood Village, CO 6 mi, 7.2 days
- Littleton, CO 9 mi, 7.2 days
Where these numbers come from
NOAA 1991–2020 climate normals from Castle Rock, 10.0 miles from Lone Tree. 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.