I don't know about the heights in the UBC, but the density of 35 pcf can't
happen. At least not around here (the Sierras of California and Nevada),
snow just can't hold that much water. It is possible to get snow/ice that
dense, but the snow pack has to be really old, where a significant portion
of snow has changed to ice. Generally this only happens late in the year
when the height (and psf) of the snow is no where near maximum.
In this area the Rocky Mountain Conversion Density (RMCD) is more accurate
in determining density. A discussion of the UBC density and RMCD is
contained in the "Snow Load Analysis for Washington", put out by SEAOW.
here are some approximate RMCD densities
Pg(psf) -- D(pcf)
20 -- 11
40 -- 16
60 -- 18
80 -- 20
100 -- 22
120 -- 22.5
140 -- 23
180 -- 24
I hope this helps,
Randy Vogelgesang S.E.
South Lake Tahoe
----- Original Message -----
From: "Matt Melcher" <MattM(--nospam--at)lbdg.com>
Sent: Thursday, March 29, 2001 4:09 PM
Subject: Snow Depth
> Snow loads for the 97 UBC are covered in the Appendix for chapter 16.
> the ground snow load and using these formulas you can determine the
> of the base of the snow, and "height" of the drift of the snow. These
> heights are based on a density of snow up to a maximum of 35 pcf.
> I have a project with windows and exhaust vents that are subject to being
> buried by snow drifts. Is using a height determined from the appendix
> unconservative for placing windows and exhaust vents?
> Anyone with some experience with this? Any good references that talk
> how these values are determined?