Light

ZIP Code 59640

Lewis and Clark County, Montana — Marysville

20PSF (Ground Snow Load)
LightClassification

What This Means

Lewis and Clark County, Montana has a light ground snow load of 20 PSF per ASCE 7-22. At this level, most standard residential roofs are designed to handle the load without issue. However, flat or low-slope roofs should still be checked for drifting and sliding snow.

Snow Load Details

ZIP Code59640
CountyLewis and Clark
CityMarysville
StateMontana (MT)
Ground Snow Load20 PSF — Light
Classification Range1 - 20 PSF
Data QualityMeasured

Source: ASCE 7-22 ground snow load polygons via ArcGIS

Roof Snow Load Calculator

ASCE 7-22 flat roof formula:  pf = 0.7 × Ce × Ct × Is × pg

Your ground snow load (pg): 20 PSF

Roof Snow Load: 14 PSF

ⓘ Simplified estimate for flat roofs. Sloped roofs, drift zones, and unbalanced loads need additional calculations. Consult a structural engineer for final design.

Lewis and Clark County Snow Load Map

Counties colored by snow load classification. Gray = No Load, Blue = Light, Amber = Moderate, Orange = Heavy, Red = Extreme, Purple = Case Study.

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Nearby ZIP Codes

59638 20 PSF Light 59639 CS Case Study 59641 20 PSF Light 59642 CS Case Study 59643 20 PSF Light

Frequently Asked Questions

What is the ground snow load for ZIP code 59640?

ZIP code 59640 is in Lewis and Clark County, Montana, with a ground snow load of 20 PSF, classified as light per ASCE 7-22.

Is my roof strong enough for snow in 59640?

With a light ground snow load of 20 PSF, standard residential construction typically handles this load, but verify with your local building code.

What county is ZIP code 59640 in?

ZIP code 59640 is in Lewis and Clark County, Montana (MT).