WINTER WEATHER

What is the Hazard?
What is the Risk?
How to Manage the Risk?

How to Manage the Risk?

Strategies for managing winter-weather risks include placing regulatory controls on building design, strengthening building maintenance and retrofits, adding infrastructure protections, putting environmental controls in place, and continuing efforts to help New Yorkers prepare for and respond to severe weather events.

Regulatory requirements to mitigate risk from winter weather take the form of increasingly robust engineering requirements in New York City's Construction Codes that require designs for new buildings to conform to standards that enhance their ability to withstand winter storms and extreme cold, specifically:

  • Roofs must be able to withstand snow load (the weight of snow on the roof) and snowdrifts caused by parapets on adjacent buildings.
  • Windows must provide thermal protection and buildings must be insulated against extreme cold.

Snow load is a moderate concern in New York City. As early as 1899, the New York City Building Code specified minimum design loads (the weight a roof can hold), load combinations, and procedures to determine snow loads. New York City’s Department of Buildings (DOB) determines snow loads based upon regional climate values for ground snow load that incorporate thermal factors for heated and unheated buildings.

In 2014, the DOB revised the Building Code to follow the most recent national standards for determining snow load, snowdrift loads, and sliding snow loads.

New York City’s construction codes apply to newer buildings any time they undergo substantial change. The DOB also plans to adopt a code specific to existing buildings based on the International Existing Building Code, which is intended to simplify building upgrade regulation and help streamline permitting for resiliency improvements.

Regular inspections that encourage ongoing maintenance and encouraging retrofitting so that buildings will better withstand winter weather are two strategies to help protect buildings from extreme cold and heavy snowfall.

The DOB considers regular maintenance and repair essential to protect residents and workers from the hazards of winter weather, and encourages periodic inspection to identify when and where repairs are needed.

Building maintenance activities that New York City encourages are:

  • Regularly inspecting building elements including parapets, cornices, window lintels, exterior walls, and roofs
  • Clearing roofs and overhangs of snow and ice, and cleaning gutters and roof drains before and after snow or ice storms
  • Regularly inspecting roof structure for wood rot
  • Inspecting and repairing all wood that has rot (especially when rot is close to outside walls)
  • Repairing sagging ceilings so they can better withstand snow load
  • Replacing all damaged roof joists.
Retrofits and upgrades that use higher-performing building materials help buildings retain heat and better withstand severe winter weather.

High-Performing Building Practices and Materials

Source: Urban Green Council

Recommended measures include:

How High-Performance Out-Performs

A high-performance building (a building that integrates energy efficiency, durability, life-cycle performance, and occupant productivity) can retain heat longer than other building types during a power outage.

The Urban Green Council found that during a weeklong power outage, the inside temperature difference between a typical building and the same type of high-performance building was 18°F to 27°F. The high-performance building also retained heat longer, with temperatures above 54°F.
  • Caulking air-seal doors and windows
  • Installing insulation and high-performance windows, such as multi-paned windows with reflective coatings that lower heat loss and potentially reduce heating costs
  • Understanding that insulated walls retain building heat better than glass
  • Protecting internal building infrastructure by fitting exposed pipes with insulation sleeves or other wrapping to slow heat transfer
  • Sealing cracks and holes in outside walls and foundations near water pipes with caulking
  • Adding insulation indoors or a new exterior layer
  • Caulking and sealing air ventilation systems to eliminate drafts.

For old and new buildings, adding a backup generator is a good insurance measure to reduce risk from possible power outages caused by winter storms. However, generators should never be run indoors and should be placed well away from doors and windows.

A promising strategy to mitigate risk from winter weather is the use of alternative pavement materials to accelerate snowmelt on streets and sidewalks. A recent study suggests that using permeable pavements noticeably improves the acceleration of snow and ice melt and reduces the need for snow plowing.

This solution would reduce New York City’s reliance upon spreading salt, deploying armies of snowplows, and using chains on vehicle tires, which all damage city streets. Implementing strategies to enhance the City’s ability to clear paved areas more quickly would also reduce the number of winter traffic accidents and improve access for emergency responders.

The City's Department of Environmental Protection (DEP) is planning demonstration projects to monitor how well permeable pavement materials accelerate snow and ice melt at three locations. The projects are required by Local Law 80 (enacted in 2013), which directs DEP to study alternative roadway and sidewalk materials. Their study will examine:

  • Various types of permeable materials
  • Expected costs
  • Ease of installation
  • Material performance
  • Absorbtion rates
  • Long-term maintenance requirements.

Another complementary strategy relies on using green infrastructure – such as bioswales and green roofs – to capture ice and snowmelt so that it does not reach and overwhelm wastewater treatment plants, which leads to raw sewage discharged into water bodies in and around New York.

The DEP’s NYC Green Infrastructure Plan employs many initiatives to help the City achieve compliance with federal water quality regulations.

A very simple measure for protecting infrastructure is deployed by the MTA. To protect its trains from risk during winter weather, the MTA stores trains underground when forecasts predict temperatures dipping to 10°F below zero, ice storms, icy conditions, or more than five inches of snow.

Tree pruning and tree maintenance strategies lower the risk that the weight of snow and ice will break tree branches and take down power lines during winter months.

New York City’s Department of Parks and Recreation’s Forestry Division oversees block pruning, which requires all street trees on a block to be pruned. Contractors perform this service on a seven-to-eight-year schedule. The Forestry Division also prunes trees in city parks.

To maintain reliable service, the city's major utility, Con Edison, manages a tree maintenance program that trims branches along right of ways to ensure that trees do not encroach upon power lines during icy winter conditions.

Helping the public understand how to prepare for and respond to winter weather events is a major priority for New York City, which engages in two types of communications initiatives -- communicating with the public immediately before and during a winter weather event, and longer-term educational initiatives to prepare households and property owners.

Immediate communication initiatives when a winter weather event threatens and occurs include:

  • Sending emergency alerts prior to severe winter weather events, taking care to target populations with disabilities, access, and functional needs, creating and distributing multi-lingual communications, and reaching out to people who are homeless.
  • Sending weather notifications to property owners, contractors, and developers, to advise them of preventative actions they can take to protect property from a winter storm before it hits, such as clearing gutters and removing snow and/or ice from roofs.
  • For major storms or prolonged periods of extreme cold, coordinating with multiple City agencies to communicate an accurate, consistent message about weather conditions and what New Yorkers can do to prepare for it. Severe weather events may require mayoral press conferences.
  • Utilizing the widest number of media channels for communications -- social media, press releases, notifications to elected officials, and emergency alert systems. Social media channels are highly effective in providing New Yorkers with real-time updates as weather conditions worsen or improve.
  • To prepare for hazardous winter weather, communicating and promoting assistance that New York City provides to residents. For example, the Home Energy Assistance Program (HEAP) helps qualifying residents to heat their homes.

New York City issues a Cold Weather Alert to the public whenever wind-chill or air temperatures are forecasted to fall below 32°F between 4 PM and 8 AM. Upon the issuance of a Cold Weather Alert, the City will increase its outreach to the homeless population. The New York City Police Department monitors the city for homeless individuals and transports them to shelters run by New York City’s Department of Homeless Services or to city hospitals as necessary.  The Metropolitan Transportation Authority also monitors areas in and around stations in the transit system to identify individuals that need shelter and to notify appropriate agencies that can help.

The New York City Emergency Management Department (NYCEM) takes the lead on other winter-storm communications. Notify NYC is the City's official source of information about emergency situations, including severe winter weather events. NYCEM sends notifications to a quarter of a million subscribers and Twitter followers.

NYCEM's Advance Warning System works through agencies and organizations that serve populations with access and functional needs to reach those segments of the city’s population. NYCEM uses email, conference calls, and a website to target and deliver information about weather conditions to individuals with special needs if an impending hazard event puts them at risk. The system is frequently used when winter storms or extended periods of extreme cold are forecast.

The best way for New York City to keep its residents safe from winter weather events over the long term is to undertake initiatives to:

  • Help the public learn how to prepare for severe winter weather events.
  • Help homeowners learn how to maintain buildings to reduce heat loss, roof leaks, and roof collapses.
  • Help households to understand the potentially lethal dangers of carbon monoxide poisoning that can be caused by gas appliances in their homes.

NYCEM's Ready New York: Preparing for Emergencies in New York City identifies steps that households can take to prepare for prolonged cold weather and winter storms, including the recommended safety precautions related to home heating equipment. The Ready New York Reduce Your Risk Guide explains how New Yorkers, and particularly homeowners, can reduce risks related to winter weather.

New York City’s Department of Buildings issues inclement weather advisories to advise property owners, builders, and contractors on the precautionary steps they should take to prepare for winter storms, such as clearing snow and ice from roofs, overhangs, and gutters; tying down and securing material and loose debris at construction sites; covering electrical equipment to minimize its exposure to the weather; and securing netting, scaffolding, and sidewalk sheds.

New York City’s Department of Health and Mental Hygiene (DOHMH) website presents information about carbon monoxide poisoning that covers its causes, the symptoms, and recommended preventive measures. A brochure developed jointly by DOHMH, New York City’s Health and Hospitals Corporation, and the NYC Poison Control Center explains how to prevent carbon monoxide poisoning. In addition, DOHMH provides general preparedness information about preventative measures to take to lessen the impact of winter and cold weather.

DOHMH conducts outreach to the general public, community organizations, and services agencies to encourage everyone to check on clients, neighbors, family, and friends who may be at increased risk during winter weather. DOHMH outreach includes social media posts, workshops and training sessions, and direct electronic communications to partners.

Link: Winter Weather Bibliography