Goose Bumps

Last question:

What causes avalanches?

Answer:

An explosion or perhaps a gunshot can rigger an avalanche, but it is more likely the result of someone being in the wrong place at the wrong time. Stepping, skiing, or snowmobiling across a weak spot in the snow can cause a huge slab of snow to split off and tumble down the slope.

Today’s Question:

Why do you get Goose bumps? What purpose do they serve?