March 6, 2023, Pollock Pines, CA — On the tail end of what has been a monstrous storm for much of our area, a new storm system is anticipated to bring heavy rains beginning as early as Thursday night. This storm is being referred to as an 'atmospheric river' and will bring a new threat of flooding and possibly snow collapse conditions in our higher elevation communities like Pollock Pines.
Residents and business owners should assess snow conditions on their buildings and take necessary measures to prevent collapse and other snow related issues such as blocked mechanical equipment, roof leaks due to ice dams, and even carbon monoxide poisoning due to blocked vents. This is especially important for buildings constructed prior to 1982 when El Dorado County adopted a design standard that addressed roof design and snow loads.
If snow accumulation remains on roofs that are not designed for snow loads, the coming rain will rapidly add weight that could trigger failures. Flat roofs, like those on mobile homes, are especially vulnerable.
Overstressed roofs typically display some warning signs. Wood and steel structures may show noticeable signs of excessive ceiling or roof sagging before failure. The following warning signs are common in wood, metal, and steel constructed buildings:
- Sagging ceiling tiles or boards, ceiling boards falling out of the ceiling grid, and/or sagging sprinkler lines and sprinkler heads
- Sprinkler heads deflecting below suspended ceilings
- Popping, cracking, and creaking noises
- Sagging roof members, including metal decking or plywood sheathing
- Bowing truss bottom chords or web members
- Doors and/or windows that can no longer be opened or closed
- Cracked or split wood members
- Cracks in walls or masonry
- Severe roof leaks
- Excessive accumulation of water at non-drainage locations on low slope roofs
Roof vents, chimneys and flues should also be monitored for blockage due to snow buildup. These systems need unobstructed access to outside air to properly ventilate. Blockages can cause carbon monoxide to backup in buildings. The heavy snow may also cause chimneys to shift, causing them to crumble or fall.
If snow removal from your roof is indicated, the work should only be completed by those with the proper safety equipment. Special care should also be taken to not damage the roof, vents, utilities (such as solar systems) or any other components of on the roof structure. If a building appears to be structurally compromised, snow removal work should cease and the building should be evacuated.
For more information, please refer to the Federal Emergency Management Administration (FEMA) Snow Load Safety Guidance.