How to Keep Buildings Safe During Blizzards
This winter New York City has experienced record-breaking snowfall. With the latest snowstorm at the end of January, the city received about 19 inches of snow in what has become the snowiest January in more than a century of record keeping. The average winter in New York City brings 21 inches of snow; this winter there has been more than 50 inches. The abundance of snow has already caused the city to go over-budget on snow removal with nearly a month of winter yet to go. New York City spent almost all of its $38 million budget before the first of the year because of the blizzard that hit the day after Christmas.
As the city was sorting through its budget and snow removal strategies, the National Weather Service and Department of Buildings (DOB) urged building owners in advance of a February ice storm to clear rooftops, awnings, and overhangs of snow to avoid potential collapses. The agency warnings came as a result of the high winds, freezing rain, subzero temperatures, and thick ice coupled with layers of packed snow that have produced a phenomenon no one expected this winter—collapsing roofs around the Northeast. Roof collapses occurred at a Massachusetts gas station, a Rhode Island elementary school, and a former car dealership in Connecticut, to name a few. Fortunately, the DOB has recorded no roof collapses in New York City caused by the most recent snowstorms.
In anticipation of a blizzard or other extreme winter event, the following are some guidelines to follow to keep your tenants safe and your building properly maintained. These principles are important to keep in mind if another major snowstorm hits New York before winter ends—or if the following winter is anything like this one.
Ground Snow Removal
“As this winter's storms have already shown, snow accumulation can wreak havoc on business-as-usual,” says Richard Gallagher, head of property risk management at Zurich Services Corporation. Ground snow removal is not only a concern due to pedestrian safety, but also because snow accumulation in certain areas around the building can affect emergency response times and harm building components such as drainage systems. Gallagher recommends checking the following items before and during a storm to help manage the snow accumulation:
- Verify that snow removal personnel are not pushing snow up against roof drain outlets. Snow should be cleared from around the outlets so that water can easily escape.
- Verify that your fire protection equipment, hydrants, and control valves remain accessible. Snow should be removed from around this equipment, which may require some hand shoveling.
- All doorways should be accessible and snow should be removed to allow egress. This is especially important for emergency exits.
Roof Snow Removal
Under Section 28-301.1 of the Administrative Code of the City of New York, property owners are legally obligated to maintain their properties in a safe condition. The last weather advisory sent out by the DOB reminded owners to prepare their properties for inclement weather and stated that it could not be read to suggest that the DOB, rather than the property owner, is responsible for maintaining his or her building.
Rooftops at the highest risk are those with wide unsupported spans, flat rooftops, and rooftops with minimal slopes. The weight of neglected snow on rooftops puts pressure on building structures. But snow left on the roof after a snowstorm is also a hazard because of ice dams.
Ice dams occur when heat leaks into the space under the roof and melts the underside of the snow on the roof. The melted snow then flows down the roof surface until it reaches a cold spot, where it forms a frozen dam, behind which more snowmelt and ice pile up. The ice buildup can back up under the shingles or other roofing element, damaging them and allowing water to leak into the building below. Here are some things to consider when dealing with snow accumulation on the roof of your building:
- In the event you need to remove snow from the roof, Gallagher strongly recommends that you solicit the services of a qualified roofing contractor and ensure that all Occupational Safety and Health Administration (OSHA) guidelines are strictly followed.
- Roof drains should be inspected to ensure that they are clear of snow and ice. An area around each drain should be cleared to allow water to reach the drain.
- The roof covering can be easily damaged, so plastic shovels should be utilized for snow and ice removal.
- The use of calcium chloride is an effective way of keeping ice from accumulating in your drains.
High Wind Conditions
Strong winds can pick up loose building material and potentially injure anyone around. The DOB warned that buildings that have been subject to deferred maintenance or in delicate condition could be at greater risk for building components coming loose during snowfall and wind gusts. Beyond anchoring objects and securing patio umbrellas and retractable awnings, here are additional things to do in anticipation of a major snowstorm:
- Check the roof for loose flashing. If the flashing is found to be loose, it should be secured with #8 (minimum) corrosion-resistant screws. The screw should have a large pan head or a washer should be used.
- Check for loose rooftop equipment. Rooftop equipment may also include satellite dishes, electrical conduit, lightning protection, and piping systems. Secure or remove any equipment that is loose and may be dislodged in high winds.
- Remove any debris from the roof.
- Remove any ground-level trash, debris, seasonal equipment, or other items that can become projectiles in high winds.
- Continue to monitor the exterior of the building to ensure no glass gets broken. Broken glass can lead to localized freezing of water-based systems. Any damage to the building envelope should be temporarily sealed until more permanent repairs can be made.
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