Natural and Unnatural Accumulation of Snow and Ice

On the Scene E-Newsletter, Edition 153, January 26, 2012

When an individual slips and falls on snow or ice, many courts rely on a jury to determine if the accumulation of snow or ice is unnatural or created by natural causes. Each municipality has its own ordinances or codes dealing with snow and ice removal.  States and counties may have statutory and/or case laws that establish or influence the level of care or specific activities associated with proper removal or treatment of snow and ice. Some duty of care is typically owed to pedestrians on property and juries are often asked to decide if snow and ice removal efforts were reasonable.  To make it even more confusing, a few states make no distinction between natural vs. unnatural accumulation of snow and ice and indicate defendants owe a duty to keep the walkway safe regardless of the source of the snow and ice.

For those locales distinguishing between different types of accumulation, an understanding of natural and unnatural accumulations of snow and ice is necessary to explain your case. You need to know it may be a natural accumulation when, during a storm, snow and ice collects on sidewalks and roads and blows under bridges or on coverings by the wind.  In other words, there is no human interference.

It may become an unnatural accumulation when there is human interference such as (1) the snow is moved by plows, snow shovels or snow blowers; (2) the snow piles melt and cause icy patches; (3) an awning protects a patch of ice from the sun; or (4) a downspout or roof edge allows water to drain on walkways which changes to ice in freezing temperatures.

You may ask:  “Do I have to shovel the snow or can I just leave it on the sidewalk and parking lot?”  The catch is that most state and local municipal ordinances require owners to clear public walkways, accessible parking areas and parking lots.  Per these codes, owners shall prevent sidewalks from being dangerous for pedestrian travel through the use of sand, salt, or other abrasives.  Also at shopping facilities the ADA codes indicate that building owners must keep accessible spaces free of snow during the winter.

However, sometimes plows load the aisles with snow and the wheelchair user does not have sufficient room to get out of the car causing a hazard from what may be the unnatural accumulation of snow.  Black ice can occur in spite of these efforts, making driving or walking on the affected surface exceedingly dangerous.   (Black ice is a thin coating of ice that is transparent on black asphalt.) 

CED engineers understand that frost or black ice naturally forms when the pavement surface cools to a temperature colder than the dew point of the air above it. When this occurs, water vapor condenses on the pavement surface and forms ice.  If the engineer looks at weather conditions that occurred on the date of the incident, they can determine if those conditions were present at the time of the incident.  The engineer also evaluates the businesses’ snow removal and deicing policies and routines during that same period to help determine if the snow and ice removal efforts were reasonable.

So what happens when someone falls outside a building?  CED engineers evaluate the following:  Was the pavement uneven, slippery or covered in snow and ice?  Were the weather conditions right for black ice formation?  Was there a natural accumulation of snow & ice or was the hazard created by human interference?   Also, in these types of accidents, conditions change quickly, Spring arrives, and snow melts.  What can be done days, months or even years after an outside slip and fall to determine causation?  To answer these questions, the engineer looks at all the evidence.  They perform a site inspection, if possible, and review the following items to help make their determination:

1. Photographs of the scene
2. Documentation of the accident
3. Witness statements
4. Accident victim’s statement
5. Medical records
6. Snow removal activities
7. Climatological data

All of these items put together reveal a picture of what really happened and with the knowledge of natural and unnatural accumulation of ice, the engineer can determine whether there were reasonable removal efforts and did the slip or trip happen as described.

In conclusion, to help avoid these types of accidents, when walking on snow or ice, individuals should wear boots with high traction soles and avoid walking or driving in areas not cleared of snow, shoveled or salted. Also they should try to avoid shaded areas and walking on steel or metallic plates such as sewer covers or tree grates.  However, if someone still falls and you need help to determine causation of the incident, call CED Investigative Technologies.   Many of our engineers have years of experience working on slip, trips and falls in not only outside conditions, but in indoor situations plus falls on stairways, ladders, and changes in elevation.  Call 800.780.4221 today to speak with an engineer about your case or claim.