Question 3 of 16 passage a avalanches are caused by a variety of conditions. when the temperature is cold and snow falls, the snow sticks to the ground. however, when the air temperature changes, the snow may slide away in pieces or slabs. basically, an avalanche happens when the gravity of snow heading downhill is greater than the gravity that holds snow together on the ground. steep slopes on mountains, a recent heavy snowfall, a weak layer in the snow cover, changes in the weather, and changes in pressure on the surface (such as a skier’s sudden weight) can all contribute to the creation of an avalanche. passage b avalanches happen in a series of stages. first, while the temperature is cold and there is a heavy snowfall, the snow will stick to the ground. suppose that what happens next is that the air temperature changes after the snow has fallen. then, a layer of the snow may weaken. next, suppose that a skier lands on the weakened snow. the snow may then slide away from the ground in pieces or slabs. as the slabs head downhill, their gravity is greater than the snow underneath. they may slide down a steep slope, creating a major avalanche. use the passages to answer the question. according to passage b, which phrase describes the second stage of an avalanche?