What factor makes the Khumbu Icefall more dangerous during daylight according to the text?

What factor makes the Khumbu Icefall more dangerous during daylight according to the text?

• A. It melts in the sun, making it unstable.
• B. It becomes colder and more slippery.
• C. It becomes covered in sand.
• D. It becomes dry and stable.

Answer: (A)

The key idea is that daylight increases danger because the sun melts the ice. As the iceabsorbs heat, surface meltwater forms and seeps into cracks, lubricating blocks and widening crevasses. This makes the jumble of ice—huge blocks, seracs, and hidden gaps—more mobile and unstable, so blocks can shift, tilt, or topple and water can flow into weak points, raising the risk of collapses and avalanches. The other scenarios don’t fit the situation: colder and more slippery isn’t typical of daylight heating, sand coverage isn’t a factor in the icefall, and being dry and stable is the opposite of what daylight melting does.

The key idea is that daylight increases danger because the sun melts the ice. As the iceabsorbs heat, surface meltwater forms and seeps into cracks, lubricating blocks and widening crevasses. This makes the jumble of ice—huge blocks, seracs, and hidden gaps—more mobile and unstable, so blocks can shift, tilt, or topple and water can flow into weak points, raising the risk of collapses and avalanches. The other scenarios don’t fit the situation: colder and more slippery isn’t typical of daylight heating, sand coverage isn’t a factor in the icefall, and being dry and stable is the opposite of what daylight melting does.