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Re: Snow Load in CS areas

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El Dorado County has a neat method for anyone to determine the ground snow load for their area.  You can do a 'Snow Load Information Request" by using the county's assessor's parcel number (APN) .  Check out

The County will instantly provide you with a ground snow load which you print out and include with your calculations for your plan check.  After you have the ground snow load, you can then go to the following page:  which you then determine the Exposure Coefficient as well as to how the snow load is applied.  It's a good idea to visit the site and determine whether the area is densely forested or not because the is a 20% difference in the design load.

What's unique about this system is that the County has tied all of the APN numbers into the their County Snow Load Map through their GPS system.  Therefore, you don't have to go through the use a snow load map or use the tables for the western part of the county or for the Tahoe Basin and the county assumes responsibility for the basic ground snow load (Pg).

Last year we designed a deck in the Tahoe Basin and the load was 240 psf!   I have heard of higher loads.

Note that the snow-seismic combination is also published so you don't have to call your local building department for the criteria. 

If you are interested in how this county developed these snow loads, check out this page:

Neil Moore, S.E.
neil moore and associates
shingle springs, el dorado county, california 

At 06:05 AM 5/6/2004 -0700, Jim Wilson wrote:
I am curious about how others are handling determination of ground snow loads in CS areas as defined by IBC and ASCE.  I just had a conversation with a local code official/inspector in the northeast Pennsylvania area about what criteria was required in his area.  He asked me if I was designing for 70 psf.  I responded that I was only checking an existing roof and that it had a live load capacity for about 40 psf.  He then said that should be fine and that an actual design snow loading hadn't ever been considered before.
Who is going to end up responsible for determining the loadings in these areas?  For now, it seems to come down to the structural engineer who has to stick his or her neck out and make a judgement call.
Then there is the conversation with the local architect who said he just uses 50 psf when he does design....
James Wilson, P.E.
Stroudsburg, PA

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