Which factor is crucial when establishing ice anchors?

The quality of the ice being used is paramount when establishing ice anchors because it directly affects the strength and reliability of the anchor. High-quality ice that has a solid and consistent structure will provide a stronger hold for anchoring equipment, ensuring that it can withstand the forces exerted during a rescue operation. Various qualities of ice, such as thickness, density, and crystalline structure, play a critical role in the anchor's effectiveness.

In contrast, factors such as the amount of snow on top of the ice may obscure the actual condition of the ice beneath and could potentially create weak points. Proximity to rescue teams, while logistically important, does not influence the integrity of the ice anchor itself. Lastly, the angle of the approach can affect maneuverability but does not determine the strength of the ice anchor. Thus, the quality of the ice is the essential factor in ensuring the safety and success of ice rescue techniques.