Which of the following is not necessary to start a snow avalanche?

• A. Adequate amount of snow
• B. A triggering agent
• C. Freezing temperatures to keep the snow from packing
• D. Wind packing snow

Answer: (C)

To determine which factor is not essential for the initiation of a snow avalanche, it is important to understand the conditions that typically contribute to avalanche formation. An avalanche primarily requires an adequate accumulation of snow and a triggering mechanism that destabilizes the snowpack.

An adequate amount of snow is fundamental as it provides the necessary mass that can slide down a slope when conditions allow. A triggering agent, such as the weight of a skier or a sudden temperature change, is critical as it disrupts the balance of the snowpack, leading to a potential avalanche event.

Wind packing snow can also play a significant role. Wind can transport and deposit snow in such a way that creates unstable layers prone to sliding. However, freezing temperatures, while they can affect the consistency and cohesion of the snow, are not necessary for starting an avalanche. An avalanche can occur without freezing temperatures if the conditions are right for instability, such as heavy snowfall or rapid warming.

Therefore, the necessity of freezing temperatures to maintain a packed snow state is not a fundamental requirement for avalanche initiation, making this option correct.