How much snow can my roof hold?



Snow Loads and the Structural Integrity of your Roof?

 

As winter progresses and the snow piles up, we start to wonder, how much weight can my roof hold? When should I have the snow removed?  The following information is provided to assist individual property owners in making the decision on when or if snow should be removed from a structure. Structures built in Blaine County after 1977, with a building permit, have been designed to meet a site-specific Roof Snow Load. See the chart below for the design requirements by location.  

 

North Fork to Smiley Creek   

  

150 pounds per square foot roof snow load  

North of Ketchum to North Fork   

  

125 pounds per square foot roof snow load  

West of Ketchum to western end of platted Board's Lower Ranch   

  

110 pounds per square foot roof snow load 

West of western end of platted Lower Board Ranch   

  

125 pounds per square foot roof snow load 

East of Triumph   

  

125 pounds per square foot roof snow load 

North of Bellevue to south of Ketchum   

  

100 pounds per square foot roof snow load 

Picabo to south of Bellevue   

  

  65 pounds per square foot roof snow load 

Carey Valley including south and east of Carey   

  

  50 pounds per square foot roof snow load 

*Older manufactured homes should have snow removed regularly. *

 

As a point of reference, Ground Snow Load has been calculated using the current Snow Water Equivalent (SWE) at the Chocolate Gulch SNOTEL site (approx. 11 miles north of Ketchum).  Ground snow load is calculated by using the current SWE and multiplying it by 5.2 PSF. 

 

Current Ground Snow Load at Chocolate Gulch SNOTEL site:

DATE

SNOW WATER EQUIVALENT

(SWE)

CURRENT ESTIMATED GROUND SNOW LOAD (LBS PER SQUARE FOOT)

Jan 30, 2023

10.8

56.16





This chart will be updated after each measurable snow or rain-on-snow event.

 


Keep in mind that the Roof Snow Load on your home is generally 0-30% less than the Ground Snow LoadIf you are concerned with the structural stability of your roof you may want to consider consulting with a professional engineer. Blaine County does not make recommendations on when to remove snow from roofs.


As the winter snowpack increases and piles up on and around your home. Keep an eye on your gas meter, exhaust venting for mechanical equipment and gas fireplaces. These items need to be free of snow to ensure proper function. 

 

And last but not least, look up! Be aware of your surroundings. Snow sliding from roofs can pose a real risk to people and pets, as well as damage to vehicles and other property.  Pay attention to how the snow on your roof reacts to new snow, rain-on-snow and rapidly warming temperatures. These events are potential red flags that the stability of the snow on your roof could change.   


FEMA Snow Load Safety Guidance brochure. 

 

Feel free to call with any questions. Blaine County Building Services: 208-788-5573.

Show All Answers

1. How much snow can my roof hold?
2. When do I need a building permit?
3. Do agricultural buildings require a building permit?
4. How long does the permit process take?
5. Does my application have to go to the planning and zoning commission?
6. When do I pay for my permit?
7. How do I cancel a building permit?
8. What is a deposit for the final inspection?
9. Can I get an estimate on the permit fee?