Proving that the Defendant Created the Snow or Ice Condition
One way you can prove the defendant is responsible for your slip and fall case under New York law is if you can show that they created the dangerous condition that led to your fall. A prime example of this is where the defendant shoveled the area where you fell, but did a really poor job; another example is where they re-directed the gutters or leaders so that ice accumulated in the area where you fell, instead of into a safer area without pedestrian traffic.
Proving that the Defendant Actively Knew About the Snow or Ice Condition, But Failed to Fix it in a Timely Fashion
Another way you can prove your negligence case is to show that the defendant had actual knowledge, which is legal terms is called "actual notice" of the condition, but failed to remedy it in a reasonable amount of time. One way you can do so is by showing that they were notified of the problem in writing, or even through a witness' testimony that they told the defendant about the problem long before your accident.
Proving that the Defendant Should Have Known About the Snow or Ice Condition, Yet Didn't Remedy it
The final way you can prove your slip and fall case under New York law is by demonstrating that, under the totality of the circumstances, there is no question that the defendant should have known about the dangerous condition, yet they unreasonably failed to use due care and remedy the situation. One example of this would be where several full days, or a week had passed from the end of a snow and ice storm, yet the defendant failed to remove the snow and ice despite passing by the area several times during that period.