Consider the following facts:

1. The destructive potential of avalanches results from their speed and mass.
2. Down the slope, an avalanche gains mass and volume.
3. Avalanches are rare phenomena constrained by season and endemic to only a few mountain ranges.

Which of the above is/are true?

After initiation, avalanches usually accelerate rapidly and grow in mass and volume as they entrain more snow. Avalanches are not rare or random events and are endemic to any mountain range that accumulates a standing snowpack. Avalanches are most common during winter or spring but glacier movements may cause ice and snow avalanches at any time of the year. In mountainous terrain, avalanches are among the most serious objective natural hazards affecting life and property, with their destructive capability resulting from their potential to carry enormous mass of snow at high speed.