A roof engineering monograph

Nevada Roof Snow Load Calculator

Ground snow load across the populated parts of Nevada runs roughly 0 to 120 psf (low). The calculator below is pre-loaded with a typical Nevada value of 10 psf. Change it to your confirmed site value and adjust the roof.

Case-study state. Las Vegas and the low desert are near zero; the Sierra and high basins are very high. Mountain and high-elevation sites are ASCE 7 "case study" zones: the ground snow load is driven by elevation and can be several times the lowland value, so confirm your exact site with the ASCE Hazard Tool or your building department.
Design snow load7 psf

The worksheet

ASCE 7-22
5"Design load7 psf
Fig. A · the roof section at 18.4°, snow blanket scaled to the design load.
Design roof snow load · balanced
7psf

At 18.4° the §7.3.4 minimum does not apply, so the balanced load of 7 psf governs.

10,500 lb total on 1,500 sq ft of roof plan

Flat Pf
7psf
0.7·Ce·Ct·Is·Pg
Sloped Ps
7psf
Cs 1
Minimum Pm
n/a
slope ≥ 15°
Rain-on-snow
0psf
§7.10
Unbalanced load · §7.6.1 gable
may govern

Large gable roof (W > 20 ft): windward side at 0.3·Ps, leeward side at Ps plus a drift surcharge from the ridge.

Windward
2.1 psf
Leeward base
7 psf
Leeward peak
18.7 psf

surcharge 11.7 psf over 6.13 ft · hd 1.33 ft · γ 15.3 pcf

How this was calculated

Flat-roof load Pf = 0.7 × Ce(1) × Ct(1) × Is(1) × Pg(10) = 7 psf. Sloped-roof balanced load Ps = Cs(1) × Pf = 7 psf.

Ground snow load, Pg10 psfsite input
Exposure factor, Ce1Table 7.3-1
Thermal factor, Ct1Table 7.3-2
Importance factor, Is1Table 1.5-2
Slope factor, Cs1Fig. 7.4-1
Snow density, γ15.3 pcfEq. 7.7-1
Settled depth at design load5 indesign ÷ density
  • 01Estimated snow density ≈ 15.3 pcf, so 7 psf is roughly 5 in of settled snow.
  • 02The §7.6.1 unbalanced (leeward-drift) case is computed above for this gable/hip roof; at roof steps, parapets and walls also check drift loads (§7.7) with the drift calculator, plus sliding snow (§7.9) onto anything below.
  • 03Ground snow load Pg is set by your local building department / the ASCE 7 Hazard Tool. Always confirm the value for your exact site before you build or submit.
Next stepSuppliers

Reduce the load on an existing roof

Your design roof snow load is 7 psf. If the design load is close to your roof's capacity, the cheapest fix is to keep snow off it. These are the tools that do that.

Some links are affiliate links: if you buy through them we may earn a commission at no extra cost to you. These are starting points, not engineering endorsements. Always confirm a product's rated snow load meets the design load above.

Finding your exact Nevada ground snow load

The number above is a planning value, not a permit value. For Nevada, get your site's design ground snow load from the ASCE 7 Hazard Tool or your local building department. Many Nevada jurisdictions adopt a published county or town value. Because elevation drives the value here, two nearby sites can differ a lot, so always use the value for your exact address.

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