What must be done to the hole after completing an ice dive?

After completing an ice dive, it is crucial to clearly mark the hole to prevent accidents. This step enhances safety by alerting other individuals in the vicinity to the presence of the opening in the ice, reducing the risk of someone inadvertently wandering over the hole and falling into the water below. Marking the hole can involve using brightly colored supplies, flags, or other visible indicators that can be easily recognized, especially in low-visibility conditions that are often present in winter environments.

While covering the hole, removing the ice entirely, or leaving it as is might seem like viable options, they do not prioritize safety in the same manner as clear marking does. Covering the hole could still pose a danger to anyone who is unaware of the hidden water underneath. Removing the ice entirely would not be practical or necessary and could potentially lead to further risks of collapse or instability in the surrounding ice. Leaving the hole as is without any markers significantly increases the likelihood of an accidental incident. Therefore, marking the hole is the most responsible and safe action to take after an ice dive.