Snow Loads & Icicles
A Special Weather Statement issued by The National Weather Service on January 30th read:
“After several significant snow storms over the last couple of weeks… A deep snowpack remains across a large portion of the tri- state area. A general 10 to 30 inches of snow depth remains on the ground… With the deepest snow depth values across Connecticut.”
“3 to 5 inches of snow water equivalent is in the current snowpack across the area. This results in a tremendous amount of weight per square foot.”
“There have already been reports of collapsed roofs due to the weight of the snow… And with the threat of yet another significant storm system expected during the middle of this week… Now is the time for residents and building owners to take preventative action to safely remove snow from flat roof tops and decks.”
The weight of snow varies greatly depending on the density and volume of water within the snow , with most estimates at approximately 7 lbs per cubic foot for light, dry snow to 20 lbs per cubic foot for heavy, wet snow. Based on The National Weather Service’s statement of “3 to 5 inches of snow water equivalent”, the weight of this particular snow fall could be as much as 26 lbs. per square foot.
With more snow predicted for this week, and likely to come again during the rest of February, we would like to encourage all of you to monitor the conditions of your roofs both at home and at work. Snow drifts at parapet walls, bulkheads, chimneys, etc. can cause significant additional loads for prolonged periods of time.
Canopies, signs, awnings, sidewalk bridges and other temporary structures can be at particular risk due to significant snow loads.
Although canopies, signs and awnings were likely designed to allow for the weight of some snow; depending on the age of the structure the initial design may not match current requirements. Furthermore, due to aging and weather exposure the structural framework may no longer be able to support the initial design load.
Sidewalk bridges are typically designed for significant snow loads; however individual wood planks and boards could be susceptible to failure. Additionally the combination of these significant snow loads with equipment and materials stored on the bridge could result in failure of the bridge. If you have a sidewalk bridge in place at any of your properties please have the contractor perform regular inspections to ensure that the sidewalk bridge and all of its components are stable.
A secondary effect of all of this winter’s significant snow fall is the large number and length of the icicles suspended from exterior projections, including gutters, ledges and window sills. While these icicles are very attractive to look at and bring out the inner child in all of us they can also be very dangerous. As the icicles become heavier and the temperature increases above freezing these icicles will begin to fall to the ground. Once again, both at home and at work, please take all available steps to remove icicles near all entrances, walking paths, driveways and sidewalks,
The New York City Department of Buildings has also issued an advisory encouraging the safe removal of snow and ice.
Please be careful during the difficult winter weather ahead.
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